Tafsir of Al-Baqarah 2:224-225

243

We learn from authentic Traditions that if anyone takes a thoughtless oath to do or not to do a thing and afterwards realizes that fairness demands its abrogation, he should abrogate it and expiate for it. The expiation for breaking an oath is the feeding of ten needy persons or clothing them or the liberation of a slave. If one cannot afford this, he must observe fast for three days. (Please see Al-Ma'idah, V : 89).

244

There is neither expiation nor any punishment for those oaths that one utters unawares as a by word.