Section: If he combines two contracts of different value for a single compensation—such as a currency exchange (sarf) and a sale where separation before possession is permissible, or a sale and a marriage, or a lease—for instance, if he says: "I have sold you this dinar and this garment for twenty dirhams," or "I have sold you this house and leased you the other one for one thousand," or he sold him a sword decorated with gold for silver, or "I have married you to my daughter and sold you her slave for one thousand," the contract is valid in both cases. This is because they are two distinct items, and it is permissible to take compensation for each of them individually; therefore, it is permissible to take compensation for them collectively, just as in the case of two slaves. This is one of the two opinions of al-Shafi'i. Abu al-Khattab said: There is another position regarding this, which is that it is not valid. This is the second opinion of al-Shafi'i because their legal rulings differ; for the sold item is guaranteed upon the mere occurrence of the sale, while the lease is the opposite. The first [opinion] is more correct. What they mentioned is invalidated by the case where one sells a share of property and a sword; it is valid despite the difference in their legal rulings, as preemption (shuf'a) is required in one but not the other. As for combining a contract of manumission with a pledge of payment (kitaba) and a sale, such as if he says: "I have entered into a kitaba contract with you and sold you this slave of mine for one thousand, with one hundred [due] every month," it is not valid. This is because the person under a kitaba contract, before the completion of the kitaba, is a fully owned slave, so it is not valid for him to purchase anything from his master, nor is a price established as a debt against him for his master. If the sale is void, is it valid regarding the kitaba at its prorated share? There are two narrations on this, which we will mention in the section on the separation of a transaction (tafriq al-safqa). Abu al-Khattab equated these cases with the preceding ones, saying that there are two views in all of them. What we have mentioned, if Allah Almighty wills, is more appropriate.

Section: On the separation of a transaction (tafriq al-safqa). Its meaning is to sell that which is permissible to sell and that which is not, in a single transaction for a single price. It consists of three categories. The first is to sell something known and something unknown, such as his saying: "I have sold you this mare and what is in the womb of this other mare for one thousand." This sale is void in every circumstance, and I know of no disagreement regarding its invalidity, because the unknown cannot be validly sold due to its uncertainty, and the price of the known item is [also] unknown, and there is no way to determine it, because knowing it would only be possible by prorating the price between them, and the unknown cannot be appraised, so the proration becomes impossible.