التعريف

A duty which has a substitute when it is untenable, but cannot be replaced by its substitute when it is feasible. For example: atonement for a vow by a husband making his wife unlawful to him is to free a slave, but if this is not available then fasting for two consecutive months, and if this is unfeasible then feeding sixty poor people. These substitutes are ordered, which means that feeding sixty people may not be resorted to if the husband is able to fast two months.