The view that comes closest to the truth is that the relevant value is its value at the time it was withdrawn from circulation. This is because ten fulūs remained established in his liability until they were withdrawn; that is, one minute before they were withdrawn, if the lender had demanded them, the borrower would have given him ten fulūs, and the lender would have been obliged to accept them. Since this is so, we assess their value at the time they were withdrawn.
His statement, “He must return an equivalent in the case of fungible goods, and the value in the case of other goods”: This means that when the borrower wishes to repay, he is required to return an equivalent for fungible goods, and their value for non-fungible goods, which are termed value-assessed goods.
According to the jurists of the school, fungible goods are “everything sold by measure or weight for which a salam contract is valid, and which contains no permissible workmanship.”
By our saying, “everything sold by measure or weight,” all other things are excluded, such as goods sold by number, by length or area, animals, garments, and so on.
By our saying, “for which a salam contract is valid,” we exclude things for which salam is not valid, such as perfumes, compound preparations, and the like. Such items are not fungible; rather, they are value-assessed goods.
By our saying, “which contains no permissible workmanship,” iron is sold by weight, but once it is made into vessels, it ceases to be considered a weighed commodity because it contains permissible workmanship. Gold, however, is sold by weight, and if it is made into vessels, the workmanship in this case is impermissible, so it remains a weighed commodity. Thus, if you borrow gold vessels from someone weighing ninety grams, and the gold would be worth eight thousand riyals if it were not fashioned into vessels, but ten thousand riyals as vessels, then the greater value is that of the vessels. Yet this increase is in return for prohibited workmanship and is therefore disregarded. Accordingly, we say that this is considered fungible, because the workmanship is not permissible; and since it is not permissible, it has no value. We therefore say: you must guarantee the weight of this gold, because the workmanship is not permissible.