according to the proportion of their capital. I have not found any report from Ahmad supporting what Abu Bakr said. It is said that this is an opinion derived by Abu Bakr, not a narrated report. The established position of the school (madhhab) is the first one; because the price is compensation for the item sold, and their ownership in it is equal, therefore their ownership in its compensation is [likewise] equal, just as if they had sold it by way of bargaining.

Section: Whenever they sell the item by its serial number or price tag without knowing it, or they are ignorant of the capital in a murabaha, muwada'a, or tawliya sale, or one of them is ignorant of that, or they are ignorant of the amount of profit or the amount of the discount, the sale is void. This is because knowledge of the price is a condition for the validity of the sale, so it cannot be established without it. If he sells it for one hundred in gold and silver [without specifying], the sale is not valid. This is the view of al-Shafi'i. Abu Hanifah said: It is valid, and it is divided into two halves, because an unqualified statement implies equality, just as in an admission (iqrar). Our evidence is that the amount of each one of them is unknown, so it is not valid, just as if he had said: "For one hundred, some of which is gold." As for his saying that it implies equality, this is not correct; for if he were to clarify it with something else, it would be valid. Likewise, if he admits to one hundred for him in gold and silver, the statement [to be relied upon] is his regarding the amount of each one of them.

753- Issue: He said: "And if one sells something and they disagree on its price, they must perform mutual swearing (tahaluf). If the buyer wishes, he may take it after that for what the seller said; otherwise, the sale between them is rescinded. The one to start with the oath is the seller."

The discussion of this issue is in three sections:

First: If the two parties to a sale disagree while the item is still in existence, and the seller says: "I sold it to you for twenty," and the buyer says: "Rather, for ten," and one of them has evidence, judgment is passed accordingly. If neither has evidence, they must perform mutual swearing. This is the view of Shurayh, Abu Hanifah, al-Shafi'i, and Malik in one of two reports. In the other report, the statement to be relied upon is that of the buyer with his oath. This is also the view of Abu Thawr and Zufar, because the seller is claiming an additional ten, which the buyer denies, and the statement is that of the denier.