Rosh Hashanah is the Day of Judgment for all of mankind. On this day man is judged for all of his actions, and all that will transpire and occur during the coming year is recorded.

The Talmud (Rosh Hashanah 8a) derives this from the verse (Deuteronomy 11:12) that states: The eyes of G‑d, your L-rd, are upon it [the land] from the beginning of the year until the end of the year - i.e., from Rosh Hashanah, the world is judged as to what will transpire throughout the year.

Our Sages said:

On Rosh Hashanah all of mankind pass before Him like sheep -they pass by Him one by one, one after the other, yet He scrutinizes them all with a single glance. Thus, the verse (Psalms 33:15) states: "He created all of their hearts together and understands all of their actions"; G‑d, Who is the Creator, sees all of their hearts together (with a single glance) and understands all of their actions.

R. Cruspedai said in the name of R. Yochanan: Three ledgers are opened on Rosh Hashanah: one for those who are entirely wicked, one for those who are entirely righteous, and one for those who are in the middle. The entirely righteous are immediately inscribed and sealed to live. The entirely wicked are immediately inscribed and sealed to die. The fate of those in the middle is held in balance between Rosh Hashanah and Yom Kippur.

If they have merit [i.e., if they repent), they are inscribed to live. If they do not have merit [i.e., if they fail to repent), they are inscribed to die (ibid. 16 a,b).

Rosh Hashanah was ordained as a Day of Judgment for two reasons: The first is that on this day the creation of the world was completed and it was the Divine intention that the world be ruled by the trait of strict justice. Hence, the commencement of the year was ordained as the Day of Judgment.

The second reason is, as we noted above, that on this day Adam was judged, he repented, and he was forgiven.

These two reasons are alluded to in the Musaf service of Rosh Hashanah, where we recite: For You have ordained a statute of remembrance to judge all spirits and souls, to consider a multitude of actions and creations without end. From the beginning You have made this known and from the commencement You did reveal this. This day is the commencement of Your works, a memorial of the first day- a memorial of the first day of the completely created world and of the first Day of Judgment.

Our Sages have noted: Come and see how G‑d's ways differ from the ways of man. The way of man is to judge a loving friend with good will, in order to treat him mercifully; and to judge an enemy with anger, in order to exact strict justice.

But G‑d does otherwise: He judges the entire world - including those who violate His commandments - only with good will, in the month of Tishrei. And Tishrei's numerous Festivals and mitzvot bring anew the affinity between Him and His creatures. During this month of reconciliation, G‑d welcomes man's prayer and repentance and judges him with compassion.

The teaching of the sages that each person is judged on Rosh Hashanah does not refer to whether a person will merit Gan Eden and the World to Come if he is worthy, or Gehinnom and eternal destruction if he is unworthy. Rather, man is judged on Rosh Hashanah concerning only this world: whether he is worthy of life and peace, or death and affliction.

Our Sages taught: The verse (Psalms 81:5) states: This is the day on which Your works began, a remembrance of the first day. It is a statute for Israel, judgment for the G‑d of Ya'akov. [In the Musaf prayer we continue:] And concerning the nations, it will be said then: Which for the sword and which for peace, which for famine and which for prosperity. And all beings will then be recounted to be remembered for life or for death.

This then is the manner of judgment: On Rosh Hashanah man's actions are weighed and he is written and inscribed either favorably or unfavorably regarding this world, based on that which he deserves for what he has done in this world. And when man departs to his final resting place, his actions are weighed and his portion in the world of the souls is allotted him, based on his merit (Ramban, quoted by Abudraham).

Even if a person sins throughout the year, he should not lose confidence in his capacity for repentance. Rather, he should return to the path of righteousness before judgment comes.

He should always believe that he has the ability to tip his own scales - and the scale of the entire world - to the side of merit. It is for this reason that it is customary among the whole House of Israel to be especially generous in giving charity, in performing good deeds, in the period between Rosh Hashanah and Yom Kippur.

Man is judged only according to his present actions (Rosh Hashanah 16a). Even if they are completely absorbed in sin throughout the year, G‑d Himself testifies that Israel desires to fulfill His will. Hence, if they repent as the Day of Judgment approaches and fulfill G‑d's will, they are judged as they are, and not as they were.