Is it permissible for a woman who has been divorced three times to return to her first husband after marrying another man with the intention of making herself lawful for her first husband, without the second husband's knowledge, and then fabricating problems with him to obtain a divorce or khul‘ (dissolution of marriage initiated by the wife), and would she be sinful for doing so?

A woman's intention to make herself lawful (for her first husband) through a second marriage is not considered, because divorce is not in her hands. If the woman or her guardian intended to make her lawful without the husband's knowledge, this does not affect the contract. A woman's marriage to her first husband after her divorce and the completion of her iddah from the second husband is valid, despite the impermissibility of her actions in stirring up problems and being disobedient.

Scholars differed regarding marriage with the intention of making her lawful (for her first husband) without a condition: The Hanafis and Shafiis consider it valid, though the Shafiis deem it disliked, and the woman becomes lawful for the first husband. However, the Malikis and Hanbalis consider it void, and the woman does not become lawful for the first husband, in accordance with the principle of blocking means to evil (sadd al-dhara'i) and the Hadith: "Allah has cursed the one who makes a woman lawful (for her first husband) and the one for whom she is made lawful."