Is an expiatory offering (kaffarat yamin) obligatory upon one who made a covenant with Allah to abandon a sin for a specified period, then broke his covenant, and is the covenant thereby dissolved?

If a Muslim makes a covenant with Allah to abandon a sin, this is considered a vow (nadhr) and an oath (yameen). If he commits that sin before the condition he specified is met, he has broken the covenant, and repentance and expiation for the oath become obligatory upon him.

Ibn Taymiyyah said: "Oaths, if they include the meaning of a vow, which is: that one commits to an act of obedience to Allah, then he is obligated to fulfill it, for it is a contract, a covenant, and an agreement with Allah."

The covenant is dissolved by breaking it the first time, so expiation is not repeated with the repetition of the act, unless the repetition of breaking it was intended, or if the wording of the covenant included what necessitates repetition, such as "whenever."

It is obligatory for a Muslim to avoid sins absolutely, and it is disliked to embark on making a covenant with Allah due to the prohibition against vows.