prohibition does not necessarily entail invalidity, whereas invalidity entails prohibition. The evidence is the Prophet’s statement, peace and blessings be upon him: “Do not intercept incoming traders. Whoever intercepts one of them and purchases from him, then when the owner reaches the market, he has the option [to rescind].” (1) This establishes prohibition, yet the contract is valid, for his words, “then when the owner reaches the market, he has the option,” indicate that the contract is valid. There can be no option except after a contract has been validly concluded, since the option is subsidiary to validity. The evidence that everything invalid is prohibited is the Prophet’s statement, peace and blessings be upon him: “Every condition not found in the Book of Allah is void, even if there be a hundred conditions.” (2) He said this as a warning against conditions that are not found in the Book of Allah.

The first is termed, by scholars of legal theory, a normative ruling, while the second is termed a declaratory ruling. In their terminology, whatever entails reward and punishment—or entails neither reward nor punishment—is normative; whereas whatever pertains to validity, invalidity, a condition, or an impediment is declaratory.

His statement, “It is prohibited and invalid for either of them to dispose [of it],” contains a grammatical competition between “it is prohibited” and “it is invalid”: which of the two governs? The answer is that both are possible here, because the pronoun is not explicit but implicit.

His statement, “the disposal of either of them,” means the seller and the purchaser. If the seller were to dispose of it and we were to validate his disposal, we would wrong the purchaser; and if the purchaser were to