What is the ruling on the vow made by a woman who vowed to assist her husband with half of her salary, or to contribute half of her salary to household expenses? Is it permissible for her to recant it by offering an expiation for an oath (kaffarat yameen)? What is the difference between a vow contingent on a human act and a vow contingent on a matter from Allah? And is it permissible for her husband to absolve her of this vow?

This vow is an vow of obedience that must be fulfilled, and expiation is not sufficient for it except in cases of permanent inability. As for a vow contingent upon an event occurring, it does not become obligatory to fulfill unless the contingent event occurs. A vow made to prevent or encourage oneself is called a vow of obstinacy (Nathr al-Lajaj), and its maker has the choice between fulfilling it or offering an oath expiation (kaffarat yameen). However, a vow contingent upon the occurrence of a blessing or the warding off of a misfortune must be fulfilled, and expiation is not sufficient for it. Vows are not recommended, but if she vowed to help her husband, that is originally a recommended act. The husband's waiver of the vow does not nullify it, because the right belongs to Allah the Almighty. Scholars differed concerning the validity of a vow made to a rich person, but the correct view is that it is valid for both the poor and the rich. However, the questioner should fulfill her vow and consider it a charity.