Does a divorce take effect if a husband says to his wife, "If you do such and such, then you are divorced," and she performs the action without his knowledge, knowing that she was in a state of purity during which he had intercourse with her? And if the divorce takes effect, is she obligated to inform him, or is cohabitation sufficient for reconciliation without his knowledge?

If a husband makes his wife’s divorce contingent upon her doing something, and she does it, the divorce takes effect according to the majority of scholars. The husband’s ignorance of the action, or the wife being in a period of purity during which intercourse occurred, does not prevent its occurrence. Sheikh al-Islam Ibn Taymiyyah holds the view that the divorce does not take effect if the husband did not intend it, and he is only required to pay an expiation for breaking an oath. He also holds that it does not take effect if it occurred during a period of purity in which intercourse took place. If the divorce takes effect, a return (to the marital state) occurs through intercourse thereafter, according to some scholars such as the Hanbalis and Hanafis, if it was the first or second pronouncement of divorce. The husband must be informed of the occurrence of the divorce so that he may account for it and pronounce or intend the return.