The 356th prohibition is that a man is forbidden from remarrying his divorced wife, if she was married to another man in the interim.1
The source of this commandment is G‑d's statement2 (exalted be He) [that if her second husband divorces her or dies,] "then her first husband who divorced her cannot remarry her."
The punishment for transgression of this prohibition is malkos (lashes).
The details of this mitzvah are explained in a number of passages in Yevamos.
