What is incumbent upon a husband who swore he would not have sexual intercourse with his wife until the end of the week, but then had intercourse with her before that?

If the husband swears by Allah or by one of His names or attributes, then he must offer expiation for a broken oath (kaffarat yamin): feeding ten poor people, or clothing them, or freeing a believing slave. If he cannot find any of these, then he must fast for three days.

However, if the oath was to divorce his wife, the majority of scholars hold that the divorce takes effect upon breaking the oath. In contrast, Sheikh al-Islam Ibn Taymiyyah is of the view that an oath of divorce not intended to actually bring about divorce, but rather meant as a threat or to emphasize a matter, carries the same ruling as an oath sworn by Allah. Therefore, only expiation for a broken oath is required, and the divorce does not occur.

According to the view of the majority, if the divorce takes effect, the husband can take his wife back if this divorce does not complete three divorces. If it was the third divorce, then she cannot return to him unless she marries another husband in a marriage of desire, and then the second husband divorces her after consummation.