Must I fast three days after swearing by God while I was angry that I would not do something, and then doing it, and expiating for my oath by feeding ten needy persons?

If a Muslim swears an oath and then sees that something else is better, he must expiate his oath and do that which is better, whether he is in a state of contentment or anger. The expiation for an oath is to feed ten poor persons from the average of what one feeds his own family, or to clothe ten poor persons, or to free a believing slave. These three options are on choice; and whoever is unable to do any of them, then he must fast for three days. Allah Almighty says: "Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what you intended of oaths. So its expiation is the feeding of ten poor persons from the average of that which you feed your [own] families or clothing them or the freeing of a slave. But whoever finds not [the means to do so] - then a fast of three days. That is the expiation for oaths when you have sworn. And guard your oaths. Thus does Allah make clear to you His verses that you may be grateful." (Al-Ma'idah: 89). Therefore, fasting is not obligatory if feeding or clothing or paying their value has been done, with the different schools of thought regarding the sufficiency of paying the value.