What is the expiation for an oath of divorce for a husband who swore to his wife that she would not do a certain thing, and is it counted as a divorce, and is it permissible to fast as an alternative if one is unable to pay money?

If the husband makes his wife's divorce contingent upon her doing something, the way to avoid the divorce is for the wife not to do that thing. If she does it, divorce occurs according to the majority of scholars. However, according to Sheikh Al-Islam Ibn Taymiyyah, if he did not intend divorce, he is liable for an expiation for a broken oath (kaffarat yamin). The husband cannot retract this contingent divorce. According to the majority, an oath of divorce is dissolved upon the occurrence of the breach, and the husband can take his wife back if this is not the third divorce.