of his ownership⦗1⦘; it is not enough merely to place him under a manumission contract. If a sale is combined with a manumission contract, or a sale is coupled with a currency-exchange transaction, the agreement is valid only for the sale, and the price is apportioned between the two parts.

It is forbidden to sell over your brother’s sale—for example, saying to one who has bought an article for ten, “I will give you the same for nine”—and equally forbidden to buy over his purchase, as when someone says to a seller who has sold an item for nine, “I will pay you ten for it,” so that the seller rescinds and contracts with him instead. In both cases the contract is void.

Whoever sells a ribā-liable commodity on deferred payment and then, in lieu of its price, receives something that may not be exchanged for it on credit, or who buys the same item for cash at a price lower than that for which he sold it on credit—though not the reverse—the transaction is invalid. If, however, he buys it for something of a different genus, or after taking possession of its price, or after its qualities have changed, or from someone other than the original purchaser, or if his father or his son is the buyer, the transaction is permissible.