When a man has more than one wife, he is duty-bound to allot his nights among them equally. Allah says, “Live with them in kindness” (4:19), and He also says, “So do not incline wholly to one and leave another hanging” (4:129). To favor some wives over others is a tilt that abandons the neglected wife in a state of suspension.

The pivot of this apportionment is the night and the overnight stay, for it is then that a person ordinarily returns home, relaxes with his family, and sleeps in his bed beside his wife. If his livelihood keeps him out at night—such as a watchman—he must divide the daytime hours instead; for him, the day counts as the night would for others.

A share must likewise be given to any wife who is menstruating, in post-partum bleeding, or ill, because the purpose is tranquility and companionship, both of which are achieved by spending the night with her even when intercourse is not possible.

He may not begin the rotation with one wife ahead of the others except by drawing lots or with their consent, for to start with her alone is preferential treatment while equality is obligatory. Nor may he travel with one of them unless lots are drawn or the others agree, for whenever the Prophet ﷺ intended to set out on a journey, he would cast lots among his wives, and the one whose name was drawn would accompany him.