Rambam - 3 Chapters a Day

If one of them is unacceptable as a witness, their testimony is no loner effective. Hence they are not punished (Kessef Mishneh).

The second pair of witnesses states that one, but not the other of the first pair were with them in a different place at the time they claim that the event transpired.

For the punishment was prescribed only for a pair of witnesses (Rashi, Makkot 5b).

As described in Chapter 13.

As described in Chapters 10-12.

As stated in Chapter 10, Halachah 4. They are, however, acceptable in matters where leniency is granted with regard to the acceptance of testimony, e.g., testimony concerning the death of a woman’s husband.

Our translation is based on the gloss of the Kessef Mishneh who states that with this phrase, the Rambam is trying to convey the following fundamental principle: Capital punishment is not given for a crime unless it is explicitly stated in the Torah. A logical proof is not sufficient.
What is the logic here? If a person who conspires to have a person executed should be executed, should not one who actually caused him to be executed.

From the Rambam’s Commentary to the Mishnah and from the gloss of the Radbaz, it appears that although they are not executed, they should be punished by the court.

I.e., what they conspired.

I.e., the Torah prescribes punishment only in such a situation.

The Ra’avad and the Kessef Mishneh question the Rambam’s source for this distinction. The Kessef Mishneh explains that it is possible to say that since judgment is ultimately in God’s hands, had the executed party not been guilty, God would not have allowed him to be executed. Hence the lying witnesses need not be punished. Alternatively, it can be explained that the punishments inflicted by the courts are not goals in their own right, but means to bring a person to atonement. It is not fitting to give lying witnesses who had a person executed the opportunity to achieve such atonement. Since lashes is not as severe a punishment, neither of these explanations apply.

I.e., the plaintiff is required to return it.

For financial penalties are established based on Talmudic logic (Kessef Mishneh).

As the Rambam continues to explain, the Hebrew term translated as “immediately after,” toch kidei dibur, has a specific meaning: The time it takes a student to greet a teacher, saying: Shalom alecha rabbi (Hilchot Sh’vuot 2:17).

The Ra’avad questions: Since these witnesses were not disqualified through hazamah, why would one think that they should be punished? The Radbaz answers that the very fact that they appeared together with lying witnesses implicates them.
The Lechem Mishneh explains that the Rambam’s intent is that even if the second pair of witnesses were also disqualified through hazamah, they are not punished. The rationale is that since their testimony was separated from that of the first pair and by the time they testified the defendant could have been executed because of the testimony of the first pair, their testimony is of no consequence. Hence they are not punished.

Thus even if there is no difficulty at all with the testimony of the last pair of witnesses, the defendant is not punished.

Because they saw the event together and appeared together in court.

The rationale for this distinction can be explained as follows: With regard to the disqualification of witnesses, everything is dependent on the testimony of the witnesses in court. Hence if their testimony is separated, they are not considered as a single group. Their classification as a single group, by contrast, depends on their coming to court together. Since they came together with the intent to testify, they are considered as a single group (Radbaz, Kessef Mishneh).
The Ra’avad (and Rashi, in his commentary to Makkot 6a) do not accept the Rambam’s approach and maintain that even though the first pair of witnesses should be executed, if the testimony of the second pair is validated, the defendant should also be executed.

I.e., he is cross-examined by the court, as explained in Chapter 2.

I.e., despite the fact that he did not actually testify, it is considered as if he did as the Rambam proceeds to explain. See also Hilchot Avodat Kochavim 2:8 which states that making such statements is equivalent to actually testifying in court.

I.e., they receive punishment even if they committed the transgression without knowing that it was forbidden.

The Radbaz explains that Numbers 15:29, the source for the laws of inadvertent transgression mentions “one who acts inadvertently” (see Hilchot Shegagot 1:2). In this context (in contrast to blasphemy), speaking is not considered as an act. Hence they are not held liable.
Nevertheless, the Radbaz and the Kessef Mishneh offer a different rationale why these witnesses are punished without a warning: They desired to have the defendant punished although he did not receive a warning. Therefore, they should be punished without a warning.

See Chapter 18, Halachah 4.

For the entire purpose of a warning is to distinguish between a transgression committed willfully and one committed inadvertently (Hilchot Sanhedrin 12:2).

See Chapter 18, Halachah 3.

We do not say that they are lying and have resolved to testify against anyone who delivers testimony in this matter (Rashi, Makkot 5a).

Because the testimony of the second group exonerates him from the onus of the testimony of the first group.

The second group should be executed as lying witnesses who sought to have the first group executed. Reuven should be executed, because once the testimony of the second group has been disqualified, the testimony of the first group is then reinstated.

Because the disqualification of the second group exonerates them.

I.e., he has a physical ailment that will cause him to die within 12 months.

Seemingly, through their testimony, they are trying to have the defendant executed. Nevertheless, despite the fact that they testify that the person who is trefe committed a murder, he is not executed. The rationale is that testimony must be able to be disqualified through hazamah. Since it is impossible to punish the witnesses “as they conspired to do to their brother,” for they conspired to have a sick person executed and they are healthy, the concept of hazamah is not relevant, as stated in Hilchot Rotzeach 2:9.

And a person who kills a colleague who is trefe is not liable for execution. For it is as if he killed a dead person (Sanhedrin 78a; Hilchot Rotze’ach 2:8).

Here also, it would appear that the intent is that since they are seeking to have the person executed, one might think that they should be executed. In fact, however, their testimony is not effective in having the defendant sentenced to death. Since they are trefe, there is no possibility of requiting them "as they conspired to do to their brother." For they conspired to have a healthy person executed and they are sick.
Accordingly, the Kessef Mishneh explains that we are speaking about a situation where the court did not recognize that the witnesses were trefe when it accepted their testimony.

Thus the punishment is not “as they conspired to do to their brother.”

For the reasons mentioned by the Rambam in the following halachah.

I.e., the descendant of a priest who is not considered as a member of the priesthood, because he was conceived in relations forbidden to his father. See Hilchot Issurei Bi'ah 19:5.

Thus making his mother forbidden to his father.
Rabbi Akiva Eiger raises a question, noting that a woman who underwent chalitzah is only forbidden to a priest by Rabbinic decree. Hence the Ramban and others rule that lashes should not be given. Rabbi Akiva Eiger himself states that since the defendant is being disqualified according to Rabbinic decree through the testimony of the witnesses, and by giving that false testimony, they violate a Scriptural commandment, it is appropriate that they be punished by lashing.

We do not say that the witnesses should be considered as challalim themselves. This applies even if the witnesses themselves are priests. Makkot 2b explains this based on Deuteronomy 19:19: “And you shall requite him as he conspired to do to his brother.” The obligation is to requite him, not to requite his descendants and having him declared a challal would be a punishment against his descendants as well as him.

The lying witnesses are not exiled “as [they] conspired to do to” the defendant. The rationale is that Deuteronomy 19:5 says with regard to a person convicted of inadvertent murder: “He shall flee to one of these cities.” Makkot, loc. cit., states: “‘He,’ and not those who conspire against him.’”

For an atonement fine is not a monetary assessment, but rather a fine designated to bring atonement for the death of the victim. These witnesses do not need that type of atonement, for their ox did not cause death (Rashi, Makkot, loc. cit.; see also Hilchot Nizkei Mammon 10:4-5).
See also the Ketzot HaChoshen 38:2 which explains that even though the witness also caused the ox to be sentenced to death and no benefit to be derived from it. Nevertheless, the witnesses are lashed and not subjected to these penalties. See also the Ramban who differs and maintains that the witnesses are required to make financial restitution and are not lashed.

The Nimukei Mahari (based on Makkot, loc. cit.), explains that the intent is that the witnesses testify that the person stole and did not have the money to make restitution for the theft.

Although Makkot, loc. cit., outlines how each of these concepts is derived from the exegesis of a verse, since the concepts are not derived through the Thirteen Principles of Biblical Exegesis, the exegesis is considered as only an asmachta. The binding obligation to fulfill these directives stems from the fact that they were transmitted through the Oral Tradition (Radbaz).

The Rambam is borrowing the wording of Deuteronomy 25:1-2: “And they shall validate the righteous and condemn the wicked. If the wicked man is deserving of being beaten...” which continues to speak of the punishment of lashing.
“Condemning the righteous” refers to a situation where lying witnesses caused judgment to be rendered against a righteous person.

In this situation, we follow the instructions of the continuation of the verse and punish the person by lashes. Delivering false testimony violates the prohibition “Do not deliver false testimony against your colleague.” Nevertheless, one might think that since that prohibition does not involve a deed, it is not punishable by lashes. Hence the exegesis of the above verse is necessary. See Makkot 4b (Radbaz, Kessef Mishneh).

As in the four cases mentioned in the previous halachah.

I.e., since the lying witnesses delivered testimony concerning a transgression punishable by lashes, there is no need for a special teaching to instruct us to give them that punishment. They are requited in this manner, because this is what they “conspired to do to their brother” (Kessef Mishneh).

See Hilchot Issurei Bi’ah 3:3 which states that the two parties to this transgression are given different punishments.

Sanhedrin 90a derives this from Deuteronomy 19:19 which speaks of requiting a lying witness, “as he conspired to do to his brother,” his brother and not his sister. This, however, is an asmachta.
Rabbi Akiva Eiger questions what the ruling would be in a situation where the witnesses claim to have given a warning to the woman, but not to the man. He supposes that even in such a situation, they should be executed by strangulation, not burning.

For this reason, we do not say that the witnesses must pay the entire amount of the ketubah. Instead, we calculate the amount as the Rambam elaborates.

Rav Moshe HaCohen, the Lechem Mishneh, and the Mishneh LiMelech emphasize that the Rambam’s intent is that the witnesses are required to pay the difference between the face value of the ketubah and the value the woman could receive for its sale immediately. It is not appropriate to require them to pay only the amount the woman would receive, for they are trying to cause the husband a loss, not the woman. There are authoritative manuscripts of the Mishneh Torah which also point to this interpretation. See also Rashi’s commentary to Makkot 3a.

And hence, likely to live for a long time and thus outlive her husband and collect the money due her by virtue of her ketubah.

People will not be willing to pay the same ratio of one tenth. Since a large sum is not involved, they are not anxious to risk their money. The Radbaz differs with the Rambam and maintains that people will be more willing to risk a smaller amount (10 zuz) to gain a relatively larger amount (100) than to risk a larger amount (100) for an immense sum (1000). A small amount (10), people will not consider significant; it’s like buying a lottery ticket. When, however, a large outlay (100) must be made at the outset, they will hesitate.

And are thus variable in every time and place according to the conditions that prevail in that society.

For this is the amount that the lying witnesses endeavored to cause him to lose.

As explained in Hilchot Nizkei Mammon 1:2, when an ox which is not known to gore gores another ox, the owner is required to pay only half the damages it caused. Since the witnesses are required to pay the amount they conspired to cause the owner to lose, they must pay this sum.

The owner of an ox that gores is not obligated to pay from his own personal financial resources (ibid 1:3). And since the owner is not required to pay more than the value of the ox, the witnesses are likewise not required.

Since it is ordinary for oxen to cause damage in this manner, the owner would have to pay the full amount of the damages (ibid. 4-5). Hence the witnesses are required to pay that sum.

In both of these instances, the master is required to free a Canaanite servant if he inflicts these injuries upon him. Since he is required to free him for the first injury, the master would be obligated to pay him financial reimbursement for the second injury.

Because through their testimony, the servant would be freed.

Because of the financial reimbursement he would have been required to make.
The Ra’avad and others have questioned the Rambam’s ruling here, noting that in Hilchot Chovel UMazik 4:11, the Rambam himself rules that if a person knocks out the tooth of his servant and then blinds [the servant’s] eye, the master is not required to pay the servant for his eye. The rationale is that since the servant did not receive his bill of release, he is not considered as possessing an independent financial capacity. If, however, the servant seizes payment for his eye from the master, he is allowed to retain possession of what he seized. Accordingly, the Ra’avad questions why the witnesses should be held liable. If the owner would not be required to pay for the eye, why should they?
The Lechem Mishneh explains that the Rambam’s intent is that if the owner seizes payment for the eye from the witnesses, he is allowed to retain possession. The Emek HaMelech states that the Rambam is indeed speaking about a situation where the master gave the servant a deed of release before damaging his eye. The Radbaz, however, gives a straightforward answer. It is very likely that the servant will seize the master’s property. Hence it is considered as if the testimony of the witnesses would have caused him this loss as well.

Bava Kama 73b states that this refers to the following situation: Witnesses testified that the master knocked out the servant's tooth and blinded his eye. Afterwards, a second pair of witnesses testified that the master blinded the servant's eye and afterwards knocked out his tooth. In doing so, they wished to reduce the payment due the servant, for the damages due for the loss of a tooth are substantially lower than those due for the loss of an eye. Therefore if it is discovered that they lied, they are required to make restitution to the servant.

Minus the worth of the tooth.

For a woman to be tried as a sotah, her husband must issue a warning in the presence of witnesses and then witnesses must observe her entering into privacy with the other man.

Only one witness is involved. Nevertheless, in this instance, the testimony of one lying witness has an effect, for- as stated in Hilchot Sotah 1:14 - we believe the word of one witness in such circumstances. Hence the laws of a lying witness apply to him.

Since they say that she committed adultery, it is obvious that they wish to deprive her of the money due her by virtue of her ketubah. For if their intent was merely to cause her to be forbidden to her husband, that is achieved by testifying that she disobeyed the warning (Merkevat HaMishneh).

For a defendant is never required both to make financial restitution and to be lashed, as stated in Chapter 18, Halachah 1.

A transgression punishable by execution.

And since she was not warned, she could not be executed (Hilchot Sanhedrin 12:1-2). Hence, the witnesses were merely conspiring to cause her financial loss. Hence, that is the punishment they are subjected to.

I.e., in the same testimony, the witnesses mention both of these points. We are forced to say this, because the Rambam maintains (Chapter 10, Halachah 4) that the testimony of a lying witness is negated retroactively and he is disqualified from the time he testified in court. Otherwise, if the witnesses were disqualified because of their statements concerning theft, they would not be obligated with regard to their statements concerning the animal’s slaughter or sale (Radbaz, Kessef Mishneh).

Thus incurring the obligation to pay four of five times the worth of the animal (Exodus 21:37).

The double payment obligated of any thief.

Since it is their testimony which causes the defendant to be obligated for the greater amount, the lying witnesses are responsible to pay that amount when they are disqualified through hazamah.

For the testimony of the first pair of witnesses obligates him.

As stated in Chapter 5, Halachah 3, when the testimony of one witness is disqualified, the legal power of the entire testimony is nullified. Since the testimony concerning the slaughter or the sale is nullified, the thief is held liable only for the double payment associated with theft. The second pair of witnesses are not liable to pay, however, for financial responsibility is incurred only when both witnesses are disqualified through hazamah (Chapter 20, Halachah 1).

I.e., not only the testimony of the first pair of witnesses, but also the testimony of the second pair. Since the entire testimony is nullified, the defendant is under no financial obligation. And since only one witness was disqualified through hazamah, none of the witnesses are liable financially.

We do not have any definite knowledge that the presumed thief obtained the animal illegally. Perhaps the owner gave it to him and he slaughtered or sold an animal that belonged to him.

As stated in Hilchot Toen ViNitan 11:2, when a person claims that a field has been sold to him and produces witnesses who testify that he benefited from its produce for three consecutive years, he is presumed to be the owner.

For through their testimony, the plaintiff’s claim to the field would have been substantiated.

Each of the witnesses paying one sixth.

Since each pair of witnesses speaks about only one year, and the claim to the field is only established when all three testimonies are joined together, one might suppose that none of the testimonies is significant in its own right. Moreover, even if the witnesses claim that they did not come to testify about the ownership of the field, merely about to whom the crops belong, we reject their claim. The rationale is that they are aware that the plaintiff is claiming ownership over the entire field and using their testimony to support his claim (Bava Batra 56a).

And hence, the value of the field is divided among all of them equally and they are not obligated to make financial restitution unless they are all disqualified through hazamah.

Despite the fact that generally the testimony of two close relatives on one matter is not accepted, in this instance the testimony is accepted, because each brother is testifying regarding a separate matter.

As explained in Hilchot Nizkei Mammon, ch. 1, when an ox has a tendency to gore (mu'ad), the owner is obligated to pay full damages for any injury it causes. When an ordinary ox (tam) causes damage by goring, by contrast, the owner is required to pay only half the amount. Witnesses must testify that an ox caused damage by goring on three occasions for the status of an ox to change.

I.e., they are not liable to pay the full damages required when an ox which is mu’ad gores. They are, however, required to pay the half-damages required for testifying that an ordinary ox gored, as stated in Halachah 3.

Based on the gloss of the Kessef Mishneh, we interpret this to mean that they are obligated to pay the decrease in the value of the ox that was caused by it being deemed as mu'ad. For from this point on, the owner would be obligated to pay full damages rather than half damages.

Since they are motioning to each other, they are obviously one group who joined together with a common intent.

The fact that they come in direct succession indicates that their intent is to have the goring ox deemed as mu’ad and not to have its owner required to pay for the other damages it caused.

In this instance, it is obvious that their intent is not to obligate the owner to pay the half-damages for the goring of an ordinary ox. For damages caused by an ordinary ox are collected only from the body of the ox itself. Since the ox is not identified, one cannot say that the witnesses had that intent. Instead, they were seeking to establish that there is a goring ox in the owner’s herd. Once this is established, he is required to watch the entire herd, lest the goring ox damage other animals. See Hilchot Nizkei Mammon 10:3.

As required when an ordinary ox gores.

The wording is taken from Deuteronomy 21:18 which speaks of parents' efforts to discipline such a son. As explained in Hilchot Mamrim, ch. 7, if the son steals from his parents and buys a feast of meat and wine, they may bring him to court and have him lashed. The description of the theft by the witnesses is the first testimony mentioned in the present halachah. Afterwards, if he steals from his parents again for such a feast, they may have him executed. The description of the second theft is the second testimony mentioned here.

And nothing more. That was the outcome of their testimony.

They cannot say that they merely intended to have him lashed, because it is already public knowledge that he was lashed.

For the “wayward son” would not be executed unless their testimonies were combined. Hence, each of them is contributing to his execution and therefore, each deserves to be executed.

For, as indicated by Deuteronomy 24:7 (see Hilchot Geneivah, ch. 9), that is the punishment which would have been given the defendant.

Although each group is testifying only about half the matter, they are still given capital punishment for the reason the Rambam explains.

There is no separate punishment for kidnapping alone. Hence, by testifying that a person kidnapped, a witnesses is already beginning the legal process leading to his execution and there is no other purpose for his testimony.

I.e., they are not even given lashes for testifying falsely, for their testimony is of no consequence.

For the witnesses to the sale could claim that they did not know that witnesses to the kidnapping would appear.

Although in Halachah 8, the fact that witnesses motioned to one another is considered significant, a distinction can be made. Those laws involve only financial penalties and this case is one involving capital punishment. In the latter instance, we are far more stringent (Radbaz, Kessef Mishneh).

The Rambam is referring to a specific situation outlined in Deuteronomy 22:13-19 and described in detail in Hilchot Na'arah, ch. 3. A husband accuses his new wife of not being a virgin. If he also brings witnesses that she committed adultery after being consecrated, her infidelity is punishable by execution.

For they desired to have the woman executed. The fact that they also sought to have her deprived of the money due her by virtue of her ketubah is not significant. For they are not punished twice - capital punishment and making financial restitution - for a wrong against the same person. See Hilchot Na’arah 1:13-14.
The Kessef Mishneh notes that in Hilchot Chovel UMazik 8:12, the Rambam rules that when a pursuer destroys utensils even those belonging to people other than the pursued, he is not held liable financially because he is liable to be killed. A differentiation can be made between that ruling and the present instance, because here the lying witnesses are punished “as they conspired to do to their brother,” i.e., according to the punishment they desired each of the involved parties to suffer. See Tosafot, Ketubot 31a.

The 100 silver pieces which Deuteronomy 22:19 obligates the husband to pay.

The principle mentioned in note 53, that a person is not executed and held liable financially for the same transgression applies only when the obligations come about because of wrongs to the same person. In this instance, the witnesses sought to wrong different individuals - the witnesses and the husband - and they must receive the punishment they conspired to have each one given.

In which case, he is executed, as stated by Deuteronomy 22:23-24.

They are not required to pay the woman the money due her by virtue of her ketubah (see the following note). Sanhedrin 10a explains that this is speaking about a situation where the witnesses do not identify the woman at all in their testimony. Since she was not singled out, she would not have been held liable. Hence, the witnesses are not liable to her.

The Radbaz explains that this is speaking about a situation where, although it is not required, the husband wrote the woman a ketubah while she was consecrated, before she was married (see Hilchot Ishut 10:11). This is the “fine” that the woman would forfeit for engaging in relations.

The money is paid to her father, because he is granted any income his daughter deserves until she attains majority.
The witnesses are held liable for both capital punishment and a financial penalty, because two different people are involved: the financial penalty is for the woman’s father and capital punishment is for the man and the woman.

Since they did not identify the ox, it is obvious that the intent of their testimony was merely to have the accused sodomizer executed. Hence, that is the punishment they are given.

In which instance, the ox would also be executed because of their testimony (Leviticus 20:15). Thus the two punishments result from two different involved parties.

As explained in Chapter 18, Halachah 2, a contradiction between two groups of witnesses refers to a situation where one group claims that an event took place, e.g., a murder was committed or a loan was given, and another group claims that the event never took place.

Since the testimony they originally gave contradicted each other, one of them was certainly not telling the truth. That person is not acceptable as a witness. Although we do not know which one - and hence cannot label either of them as a lying witness - we know that one of them is unacceptable. And thus when they come together, we are certain that at least one of the witnesses is unacceptable.
The Sefer Meirat Einayim 31:2 explains that the defendant is not even required to take an oath, as would be required when one witness testifies in support of the plaintiff. The rationale is that when one of a group of witnesses is disqualified, the entire testimony is of no consequence (Chapter 5, Halachah 3).

Since we do not know which of the groups is lying, we do not disqualify either of them. Instead, we follow the basic assumption that every Jew is acceptable as a witness (Sh’vuot 47b).

100 zuz.

I.e., the lesser sum of the two amounts.

For he is trying to expropriate funds from the person in possession (see Hilchot Malveh ViLoveh 27:15-16). Were the promissory notes to be signed by acceptable witnesses, he would be in a position of strength. In this instance, however, since one of the groups of witnesses certainly lied and is hence disqualified, the plaintiff is put at a disadvantage.

After the defendant makes the smaller payment and takes the oath, the larger promissory note is destroyed by the court, so that it could not be used again [Shulchan Aruch (Choshen Mishpat 31:2)].
The Shulchan Aruch continues, stating that the Rambam’s ruling applies only in a situation where the plaintiff demands payment for both promissory notes at the same time. If, however, he demands payment for each one individually, his claim is vindicated and the defendant is required to pay both the debts. See Halachah 4.
The Ramah adds that the defendant may require the plaintiff to take an oath that he does not possess two promissory notes. For this reason, he suggests that the plaintiff should burn the smaller promissory note so that he will at least receive payment for the larger one.

I.e., holding a Torah scroll or tefillin, as stated in Hilchot Sh’vuot 11:8.

I.e., this is a Scriptural oath, and not merely a sh’vuat hesset of Rabbinic origin.

For at least one of the groups of witnesses is acceptable.

As explained in Hilchot To’en V’Nit’an 4:10, when a plaintiff demands 100, the defendant denies the obligation entirely, and witnesses testify that he owes 50, the defendant is required to take a Scriptural oath concerning the remaining 50. The rationale is that just as he would be required to take such an oath had he admitted owing the 50 himself, he is required to take the oath when his obligation is established by the testimony of witnesses.
The Ra’avad and Rabbenu Nissim object to this ruling, explaining - as the Rambam states in Hilchot Toen ViNitan 4:4 - that when a person acknowledges a debt recorded in a promissory note, the laws concerning one who admits a portion of a debt do not apply to him. For even were he to deny the debt in this instance, his denial would not be accepted. Similarly, in the case at hand, one could claim that since there is a promissory note involved, there should be no obligation for an oath. Also, a promissory note establishes a lien against landed property and in such instances, an oath is not required.
A distinction can, however, be made. For in this instance, neither of the promissory notes have the power to enable the plaintiff to expropriate property on its basis. Hence the claim resembles one supported by a verbal commitment alone (see Kessef Mishneh, Radbaz). The Siftei Cohen 31:2, however, does not accept these resolutions and states that the Rambam’s ruling applies only when the defendant does not own land.

Since we do not know which of the claims is valid and which is using lying witnesses, we substantiate them both.

See Hilchot Malveh v’Loveh 16:5. As the Rambam states there, this oath was instituted to appease the defendant. Since he is obligated to pay two claims and one of them is not legitimate, he is at least given the satisfaction of requiring both of the plaintiffs to take oaths.

Because one - and we do not know which one - is based on the testimony of lying witnesses.

I.e., of no value.

A less severe oath required by our Sages when a defendant denies entirely a claim lodged against him.

For each of the defendants can say: “It is the pair of witnesses on the other document that are acceptable. Those who signed my document are liars.” Since we don’t know which of the defendants’ claims to accept - and one is certainly true - we decide in favor of both defendants. For whenever a person is trying to expropriate money, the burden of proof is upon him.

Rabbenu Asher and the Tur rule that the plaintiff must conduct the suits in two different courts. The Shulchan Aruch (Choshen Mishpat 31:3) quotes the Rambam’s ruling without making this clarification.

For as stated in Halachah 1, when each one of the groups comes individually, their testimony is accepted.

I.e., we look at the witnesses as we look at any group of witnesses, assuming that they are telling the truth.

For we assume that the plaintiff indeed had the legal document forged.

As the Rambam states in Chapter 8, Halachot 1 and 4, when witnesses testify with regard to their signature on a legal document, they must testify that the transaction in fact took place. Hence, we rely on their word even if the plaintiff is known to have attempted to perpetrate forgery.
The Radbaz states that even if the witnesses do not remember signing the legal document, since they remember the loan and recognize their signatures, the document is valid. We do not suspect it is a forgery.