A Vow Whose Intention is to Prevent Something Falls Under the Ruling of an Oath

Question :

I am a young man who used to be a wasteful, then Allah guided me. But I am still committing sins, and I tried to repent of them many times, but I could not, so I said to myself: "I vow that if I repeat this sin, I will fast for two months consecutively," but Satan made it appear attractive to me, so I said that a vow in these circumstances is like an oath and I must atone for it, then I repeated this sin. What should I do, may Allah reward you with goodness? Is it permissible for me to feed sixty poor persons, because that is easier for me than fasting, bearing in mind that Allah has blessed me with repentance of this sin now?

Answer:

Firstly: It is desirable that a person should have a firm, honest intention and then abandon the forbidden without swearing and without a vow. He should undertake what is obligatory without swearing and without making vows. Allah, Most High says:
"They swear by Allah their strongest oaths that if only you would order them, they would leave (their homes for fighting in Allah's Cause). Say: "Swear you not; (this) obedience (of yours) is known (to be false). Verily, Allah knows well what you do."

But a person might be unable to curb the wildness of his inner self, so he turns to making vows or swearing in order to perform his obligations or to abandon the forbidden.

The scholars may Allah have mercy on them-have said that the ruling for a vow whose intention is to prevent oneself from. doing something, or to force oneself to undertake something, is that of an oath. Therefore, it is incumbent upon the questioner to atone for his vow with the atonement for an oath. That is to feed ten poor persons with a Mudd (two handfuls) of rice or wheat. And the Sa' which we know, according to our custom here, is equal to five Mudds of the Prophetic Mudd. Or, he may clothe ten poor persons, or free a slave. And he is free to choose. from these three. If he is unable to do them, he must fast for three consecutive days, according to the Words of Allah, Most Blessed, Most High:
"Allah will not punish you for what is unintentional in your oaths, but He will punish you for your deliberate oaths; for its expiation (a deliberate oath) feed ten Masäkin (poor persons), on a scale of the average of that with which you feed your own families, or clothe them or manumit a slave. But whosoever cannot afford (that), then he should fast for three days."

It is permissible for him to prepare food, either lunch or dinner, and to invite ten poor persons to it.

Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 6 Pages 439-440