Is the husband obligated to fast two months as expiation for ẓihār if he is able to, or is it permissible for him to feed sixty poor people for fear of being unable to refrain from his wife during the fasting period?

If a man pronounces ẓihār upon his wife, sexual intercourse with her and its preliminaries become forbidden to him until he performs expiation.

The expiation is: freeing a slave before engaging in sexual intercourse. If he cannot find one, then fasting for two consecutive months before engaging in sexual intercourse. If he is unable to do that, then feeding sixty needy people. The expiation is to be performed in this specific order, not by choice.

It is obligatory for the one who pronounces ẓihār—if he does not have an illness that prevents him from fasting—to fast for two consecutive months. He is not permitted to feed the needy as long as he is capable of fasting.