His statement, “or if he exchanges it for something of a different kind—not as a means of evading zakah—the zakah year is interrupted”: In reality, an exchange is a sale. However, since the author, may Allah have mercy on him, said, “if he sells it or exchanges it,” we must understand a sale to mean a sale for cash, and an exchange to mean one involving something other than cash. This is because the basic principle of conjunction is that it indicates a difference in meaning, which requires that what is meant by exchange be something other than sale.
Thus, if he sells forty sheep for dirhams, this is a sale. But if he exchanges forty sheep for thirty cattle, this is an exchange. Otherwise, a sale is itself an exchange, as they say in defining a sale: “It is the exchange of property—even a liability—for the equivalent of one of the two …”
His statement, “or if he exchanges it for something of a different kind,” means: if he exchanges it for something of a different kind, either in actual fact or in legal ruling. An example of exchanging the type of nisab in actual fact is when he exchanges a nisab of freely grazing sheep for freely grazing cattle. In that case, the zakah year ends, because the type here is actually different. It may also be said that it differs in legal ruling, since what is due for cattle differs from what is due for sheep.
An example of exchanging the type of nisab in legal ruling is when he exchanges a nisab of freely grazing sheep for a nisab of sheep held as trade goods. The zakah year is interrupted because the ruling differs; thus, it is as though he had exchanged it for something of a different kind.
Issue: If he exchanges gold for silver—for example, if he has twenty dinars and, during the year, sells them for two hundred dirhams—the apparent meaning of the author’s statement is that the zakah year is interrupted, because gold is distinct from silver according to the explicit wording of the hadith. The Prophet, peace and blessings be upon him, said: “Gold for gold, and silver for silver … then if”