that which he lent to him as counterfeit. This may imply that he meant [the case] where he sold him the commodity with them while he knew of their defect. As for if he sold [a commodity] to him on credit for dirhams, then accepted these [counterfeit dirhams] as a replacement for it without knowing about their defect, then it is incumbent that he is entitled to dirhams free of defect, and he returns these to him. The buyer [in turn] has the right to return them to the seller as payment for the loan, and the price remains as a liability upon him. If he counts them for the seller as payment for the loan, and he pays him the price in good [currency], it is permissible. He said: If he lends a man dirhams and says, "If I die, you are absolved," it is a bequest. If he says, "If I die, you are absolved," it is invalid; because this is an absolution suspended upon a condition, and it is not valid to suspend it upon conditions. The first is a bequest, because he suspended it upon the death of himself, and a bequest is permissible. He said: If he lends him ninety dinars for one hundred in number, while the weight is the same, and they were only current in a place by weight, it is permissible. But if they were current by their number, then no; because if they were current in a place by their number, that would be an increase, since the ninety [dinars] from the hundred take the place of the ninety he lent to him, and he gains an extra ten, and it is not permissible to stipulate an increase. If they were not current except by weight, then there is no increase in them even if their number is large. He said: If he said, "Borrow a hundred for me from so-and-so, and you shall have ten," there is no harm in it. But if he said, "Guarantee [the debt] on my behalf and you shall have a thousand," it is not permissible. This is because his saying, "Borrow for me, and you shall have ten," is a commission (ju'alah) for a permissible act, so it is permissible, just as if he said, "Build this wall for me and you shall have ten." As for the guarantee (kafalah), the guarantor becomes liable for the debt, and when he pays it, he is entitled to it from the person on whose behalf he guaranteed, so it becomes like a loan. Thus, when he takes compensation, the loan becomes one that draws a benefit, so it is not permissible.

Section: We have already mentioned that the borrower returns the equivalent in fungible items, whether its price has decreased, increased, or remained the same. If the item he lent is present in its essence, and he returns it without a defect occurring to it, he is obliged to accept it, whether its price has changed or not. If a defect occurs to it, he is not obliged to accept it. If the loan was in fulus (copper coins) or broken coins, and the ruler forbade them and dealings with them were abandoned, the lender is entitled to their value, and he is not obliged to accept them, whether they are still in his possession or he has consumed them; because they became defective while in his ownership. Ahmad explicitly stated this regarding broken dirhams, and he said: He shall assess how much they were worth on the day he took them, then give it to him, regardless of whether their value decreased a little or a lot. The Qadi said: This is if people agree to abandon them; but if they continue to deal with them despite the ruler's prohibition of them, he is obliged to accept them. Malik, Al-Layth ibn Sa'd, and Al-Shafi'i said: He has no right to anything but the equivalent of what he lent him, because that is not a defect that occurred to them, so it follows the same rule as a decrease in their price. Our argument is that the ruler's prohibition of them prevented their expenditure and invalidated their status as money, so it resembles their breaking or the loss of their parts. As for a decrease in price, it does not prevent their return, whether it is significant—such as if they were ten for a daniq and became twenty for a daniq—or slight; because nothing occurred to them, rather the price changed, so it resembles wheat when it decreases or increases in price.