He Swore That He Would Not Do Something and Then He Was Compelled to do it

Question :

I went to some of my friends and they forced me to remain with them. I declared all the expense they had incurred for me to be forbidden to me, and they went and slaughtered a sheep for me, and compelled me to eat it, so I obliged them and ate, what must I do?

Answer:

You must atone for declaring something forbidden to yourself and then breaching that declaration. You must make the atonement for an unfulfilled oath, which is to feed ten poor persons with an average meal which you would feed to your family, of wheat, dates or the like, giving each poor person half a Sa'. Or, you must clothe ten poor persons, or free a slave. If you are unable to do any of these things, you must fast for three days, in compliance with the Words of Allah, Most High:

"O Prophet! Why do you forbid (for yourself) that which Allah has allowed to you, seeking to please your wives? And Allah is Oft-Forgiving, Most Merciful. Allah has already ordained for you (O men) the absolution from your oaths."

And His saying:
"O you who believe! Make not unlawful the Tayyibat (all that is good as regards foods, things, deeds, beliefs, persons) which Allah has made lawful to you."

Then Allah clarifies the characteristics of the atonement, in His Words:

"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. That is the expiation for the oaths when you have sworn.

Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 6 Pages 377-378-379