dispatch an army, and he would take, from the camels of zakah, one camel in exchange for two, and two camels in exchange for three. (1) (2) This accords with the principles, since it is based on the rationale we have mentioned.

His statement, “It is not permissible to sell a debt for a debt,” is not unrestricted; rather, it has several forms:

The first is selling a debt owed by another person. It is not permissible to sell it for a debt; indeed, according to the established school, it may not be sold even for a tangible asset, without exception.

An example is a person who owes someone one hundred sāʿ of wheat. The creditor begins demanding it, saying, “So-and-so, give me what you owe,” while the debtor keeps delaying him. Someone then says to the creditor, “We will give you one hundred dirhams for it, and we will collect it from the debtor.” This is not permissible. Even if it is purchased for a tangible asset, it is not permissible. Thus, if the person to whom So-and-so owes one hundred sāʿ is told, “We will give you one hundred riyals for it, which you will take in cash,” this is not permissible, because it resembles something whose delivery cannot be ensured. If that is the case, it involves uncertainty, for the debtor may pay in full, may not pay at all, or may pay only part of it. Therefore, it is not valid.

However, if the person who purchases So-and-so’s debt is able to collect it from him—for example, a person with authority who can recover the money owed by that man—then the sound view is that it is permissible. This was the view preferred by Shaykh al-Islam Ibn Taymiyyah, may Allah have mercy on him, because the reason for prohibiting the sale of debts owed by others is only