Those who hold that the ḥadīth must be limited to the case in which the seller’s and the buyer’s claims are evenly balanced argue as follows:

If the buyer has already taken possession of the goods—or if the goods have perished—his possession stands as a testimony in his favor and lends plausibility to his claim. An oath, they maintain, is required only from the disputant whose position carries the stronger presumption, and this is Mālik’s foundational principle concerning oaths. For that reason he sometimes obliges the plaintiff to swear and, in other instances, the defendant. The oath was not textually imposed on the defendant merely by virtue of his being the defendant; rather, it was imposed because in most circumstances the defendant enjoys the stronger presumption. Consequently, whenever the plaintiff is the one with the stronger presumption, the oath must fall to him.

Those who say that the buyer’s word prevails reason that the seller admits the act of sale and then brings a further claim against the buyer regarding the amount of the price.

As for Dāwūd and those who follow his position, they reject the ḥadīth of Ibn Masʿūd on the grounds that its chain is disconnected (munqaṭiʿ); this, they say, is why al-Bukhārī and Muslim did not include it, whereas Mālik did record it.

Mālik himself is reported on two opinions when both contracting parties refuse to take the oath: one narration holds that the contract is rescinded; the other that the seller’s statement prevails.

Who should begin with the oath? Within the Mālikī school there is disagreement. The more widespread view is that the seller swears first, in keeping with the ḥadīth. If the contract is rescinded, may either party subsequently choose to accept the other’s claim? Here, too, the school contains divergent opinions.

[Fifth Part: General Rulings on Invalid Sales]

Fourth Category of the Shared Inquiry into Sales (namely, the ruling for a corrupt sale once it has occurred):

The scholars agree that when an invalid sale has taken place and the goods have not been lost through a subsequent contract, an increase, a decrease, or a shift in market prices, the ruling is restitution—that is, the seller must return the price and the buyer the merchandise.

They differ, however, when possession has been taken and the item has then been disposed of by emancipation, gift, pledge, or any other form of disposition: does such action constitute a loss that obliges payment of the item’s value? The same question arises if the item has increased or decreased in worth.

Al-Shāfiʿī maintains that none of this constitutes loss, that a corrupt sale creates no semblance of ownership, and that what is required is simply restitution of the very things exchanged.

Mālik, on the other hand, holds that all of these situations amount to loss that obliges payment of the value, except for what Ibn Wahb transmits from him concerning ribā—that, in that specific context, no loss is entailed. Abū Ḥanīfah expresses a similar view.

According to Mālik, invalid sales fall into two categories: those that are forbidden and those that are merely disliked. If a forbidden sale is lost, it must be settled by paying the value; if a disliked sale is lost, the contract becomes valid in his view. Indeed, some sales regarded as corrupt may be validated by mere possession, owing to the relative mildness of the dislike in those cases.

The Shāfiʿīs liken an invalid sale rooted in ribā or excessive uncertainty (gharar) to the sale of items whose very substance is prohibited—such as wine or swine—and therefore recognize no form of loss in those transactions.

Mālik, however, sees the prohibition in these matters as stemming from the absence of fairness—in other words, from ribā and gharar themselves. Hence, if the commodity is lost, equity requires reverting to its value, for the item might be received when worth one thousand, yet returned when worth only five hundred, or the reverse. For this reason Mālik considers a change in market prices to constitute loss in a corrupt sale.

Mālik also holds, in the case of a sale involving a salam (advance payment), that if the commodity is lost and the seller is the party who had received the advance, the buyer must repay the value provided it does not exceed the original price, because