What is the ruling on a husband saying to his wife, "I divorce you if I don't go" or "By divorce, I will not go," and then he goes? And does a divorce or an oath occur, whether he intended divorce, or threat, or an oath, or he intended nothing?

Divorce occurs upon breaking an oath sworn by divorce, and this is the issued fatwa. Ibn Taymiyyah holds that an oath sworn by divorce, when the intention is not to make divorce conditional, is subject to the same ruling as an oath sworn by Allah, and an expiation for an oath becomes obligatory upon breaking it. If one swears by the formula "by divorce," intending merely to swear by it out of reverence, neither divorce occurs nor is expiation due, because it is a void oath. Swearing by divorce is not legislated and one should beware of it.