Allah’s saying, “nor should they leave,” refers to leaving in the sense of departing permanently, not leaving for any reason whatsoever. This view is correct.
Another respect in which she differs from other wives is that, if a woman marries, she forfeits custody of her children. Thus, if a man divorces his wife and they have children, their mother has the greatest right to their custody until they reach seven years of age. But if she marries, her right of custody is forfeited and they return to their father. However, if she is divorced—even by a revocable divorce—the children return to her custody. In this respect, then, she differs from other wives: she is presently a wife in relation to her most recent husband, who divorced her, yet she takes custody of her children from her first husband, even though she is legally regarded as a wife in relation to the second husband.
Another respect in which she differs from other wives is that if someone establishes an endowment and says, “It is an endowment for my children; but whichever of my daughters marries shall have no share in the endowment,” then, if she is divorced—even by a revocable divorce—her right to the endowment is restored.
All these distinctions are according to the school, although the author’s wording here implies that she differs from other wives only with regard to the allotment of nights. I say that it implies this because the well-known principle among scholars is that an exception is the measure of generality; that is, when you exclude something, this indicates that the ruling is general in everything besides what has been excluded. Thus, when he said, “But she has no allotted share,” we say: in her remaining rulings, she is the same as other wives—although she differs from them in the three preceding rulings. You may not find these matters gathered together in one place in the writings of the jurists, but we have derived them by tracing their statements.