The 347th prohibition is that one is forbidden to have relations with one's neighbor's wife.
The source of this commandment is G‑d's statement,1 "do not lie carnally with your neighbor's wife."
There are various forms of punishment for one who transgresses this prohibition. If she was a betrothed maiden [na'ara m'urasa],2 she is executed by stoning, as explained in Scripture.3 If she was the daughter of a kohen, she is executed by s'reifah. He, however, is executed by strangulation.4 If she is not the daughter of a kohen and is fully married,5 both of them are executed by strangulation.
This all refers to where the testimony was accepted. If it was not, the penalty is kares.
All the above6 applies only if the transgression was done intentionally. If it was done unintentionally, a sin-offering must be brought.
This prohibition is repeated in the Ten Commandments in the verse,7 "do not commit adultery," which refers to relations with a married woman.
The Mechilta8 says, "Why does it say, 'do not commit adultery'? Because the verse,9 'both the adulterer and adulteress shall be put to death' teaches us only the punishment, not the actual prohibition.10 Therefore it says, 'do not commit adultery.' " And the Sifra says, "the verse,11 'if a man commits adultery with a married woman, and she is the wife of a fellow Jew [both the adulterer and adulteress shall be put to death]' teaches us only the punishment, not the actual prohibition. Therefore it says, 'do not commit adultery' — [to serve as the prohibition] both for the man and for the woman."
These sources do not use the verse, "do not lie carnally with your neighbor's wife" as the actual prohibition since it applies only to the man instead of both the man and woman. Similarly, our Sages had to extend the other sexual prohibitions to the woman as well [as to the man],12 as they said,13 "The verse,14 'they shall not approach to commit a sexual offense' addresses itself to two people [since it says 'they']. This comes to prohibit the man through the woman and the woman through the man."
Tractate Sanhedrin15 states, "all cases are included in the terms 'adulterer' and 'adulteress,' except that the daughter of a kohen was singled out for punishment by s'reifah, and the betrothed maiden for stoning." In our introduction16 we have already explained this statement.
