Is it valid to combine two contracts with differing values for a single consideration, such as simultaneous sale and rent, or sale and marriage?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
The contract is valid when combining two distinct transactions with a single price, provided each item could be validly transacted for separately. This applies to combining a sale (bay') and another sale where separation before receipt is permissible, or combining sale, marriage (nikah), or rent (ijarah). For example, selling a dinar and a garment for twenty dirhams, or selling a house and renting another for one thousand, or selling a gold-adorned sword for silver, or marrying one's daughter while selling her servant for one thousand, is valid. This opinion is supported by one of the two views attributed to Imam Al-Shafi'i. The validity stems from the principle that since consideration can be taken for each item individually, it can be taken for them collectively, analogous to selling two slaves together.
Supporting text
Abu Al-Khattab mentioned an alternative view, which is also the second opinion of Al-Shafi'i, stating that such a combination is invalid because the legal consequences differ; the sold item is guaranteed immediately upon sale, whereas the rented item is not guaranteed in the same manner. However, the first position is stronger, as it is supported by the validity of selling a share of land alongside a sword, despite differing rulings regarding the right of pre-emption (shufa'ah) applying to one but not the other.