The sufficient Kaffarah

Q 5: my brother vowed that he would never commit a sin again, otherwise, he would fast for three successive days as a Kaffarah (expiation) for it. Is it sufficient for him to feed ten poor people or does he have to fast?

A: It is enough for him to feed ten poor people, clothe them, or free a believing slave; if he is unable, he should fast for three days.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.