so they would bring him one thousand dirhams every day, and he would say, “Whatever remains is yours.” This is called mukhāraja: for a master to say to his slave, “Bring me one dirham every day, and whatever exceeds that is yours.” This is permissible. However, if he does not earn the dirham, he is not liable for it, because if the master were to hold him liable for it, that would not be permissible.

The apparent meaning of the author’s words, may Allah have mercy on him, is that the sale is not valid even if their values are the same. There is a difference of opinion among the scholars regarding this.

Some of them say that if the values are equal, the sale is valid. Yet this view also warrants consideration, since values may be equal despite differences in qualities. For example, one may be worth one hundred because it is fat; another may be worth one hundred because it is pregnant; and a third may be worth one hundred because it is large-bodied. Thus, equality of value in itself does not remove the uncertainty when the particular item being sold is what is intended. But when trade is what is intended, then if the values are equal, there is no uncertainty, because in trade what is sought is the price or value. Therefore, if the values are equal, there is no harm in saying that the sale is valid when trade is the intended purpose. But if the particular item sold is what is intended, it must be specified, for values may be equal while the intended purposes differ.

Another example: this is a pregnant sheep, but it is lean; this is a fat sheep, but it is small-bodied; and this is a large-bodied sheep, but it is lean. Their values are equal: pregnancy has raised the value of the pregnant one; fatness has raised the value of the small one; and its large body has raised the value of the large-bodied one with little meat. A person may have a particular interest in the pregnant one rather than the fat one, in the fat one rather than the pregnant one, or in the fat one rather than the large-bodied one.