What should a man do who used to commit a sin and vowed to fast three days if he returned to it, until a large number of fasting days accumulated for him?

The questioner : The questioner says: “May the Shaykh be respected, I used to commit a sin in the past, and I vowed that I would fast three days every time I committed it, until a large number of days accumulated for me. What must I do now?”

The Shaykh : First, you must repent to Allah from this sin, and you must have a strong resolve, and you must not let Satan and your desires overcome you into repeating this sin.
However, if you vowed to fast three days, or more, or less, every time you did it, then this vow is considered in the ruling of an oath. That is, it is permissible for you to fast the days you specified, and it is permissible for you to expiate with the expiation of an oath. If you said, “I have a vow upon me for Allah that if I return to this sin, I will fast three days,” and then you returned to it, we say: if you wish, fast three days; if you wish, expiate with the expiation of an oath. The expiation of an oath is feeding ten poor people, or clothing them, or freeing a slave. Whoever does not find the means to do so must fast three days. Yes.