Is it permissible for the first wife to donate by buying a house for her and her husband to live in, and for the husband to pay her a sum as rent for this house, given that the husband bought a house for the second wife and is no longer able to buy a house for the first?

Justice between wives regarding nighting is obligatory. As for other matters, such as maintenance and housing, scholars have differed. The husband is not obliged to house any wife in a property he owns; rather, he is obliged to provide her with private accommodation, and providing rent is considered providing housing. It is permissible for a husband to give a gift to one of his wives that he does not give to the other. What is obligatory is justice in nighting, maintenance, and similar matters. Nevertheless, it is preferable to be just between them in whatever one is capable of, due to the Prophet's (peace be upon him) saying: "Whoever has two wives and inclines to one over the other, will come on the Day of Resurrection with one of his sides drooping."