the purpose of rescission by mutual agreement is to return the exchanged considerations. If we consider taking more than her dowry disliked or forbidden, this is because the standard compensation for her release from the husband’s dominion is the amount stipulated in the marriage contract. Marital sexual rights cannot be sold, given away, or inherited as property can, or as rights of use can be leased, lent, or inherited. Trading and leasing property are permissible according to the scriptural texts and scholarly consensus.
As for merely trading in rights of use—for example, renting a house and subletting it for a higher rent without carrying out any work on it—the scholars hold two views, both reported from Ahmad. The better-known view reported from him is that this is permissible; it is also the position of most scholars, including Mālik and al-Shāfiʿī. The second is that it is impermissible, as Abū Hanīfa held. Its proponents argue that it constitutes profit from something for which one bears no liability.
The first view is more correct, because the lessee does bear the risk of losing these benefits. That is, once the leased property has been delivered to him, if he does not use it, its benefits lapse at his expense as their owner. This differs from the destruction of the leased property itself, which is comparable to fruit perishing before it ripens.
The point here is that the permissibility of trading in rights of use, which can be inherited, is itself disputed. What, then, of marital sexual rights, which can neither be given away nor inherited according to the scriptural texts and scholarly consensus? It was the people of the pre-Islamic era who used to inherit such rights, and Allah abolished that practice. Thus, if a husband wished to part with his wife and marry her to another man in order to take her dowry, he would have no right to do so. If intercourse took place with her on grounds of presumed lawfulness, the dowry would belong to her, not to him. Hence the prohibition on taking more than the dowry.
If release for compensation is likened to rescission by mutual agreement, rescission in each contract is governed by the nature of that contract. These matters are discussed at length elsewhere.