For Allah has stated that He took a covenant from the prophets and their peoples: “Whatever Scripture and wisdom I grant you, then should a messenger come to you confirming what you already possess, you must certainly believe in him and support him.” This is a command to every People of the Scripture that, whenever a subsequent messenger comes to them, they must believe in him and aid him—even though they may already have Scripture and wisdom—nor may they say, “What we possess of Scripture and wisdom suffices us; we have no need to believe in the messenger who has come to us.”

In particular, this applies to faith in Muhammad—may Allah bless him and grant him peace—for he is the Seal of the Messengers and the last envoy sent to confirm what lay before him of revelation. Accordingly, anyone to whom he is conveyed is obliged to believe in him and to support him, regardless of whatever Scripture and wisdom he already holds.

Allah took this covenant from the prophets, and they in turn took it from their nations. Then He said: “Do they, then, seek a religion other than Allah’s?” (3:83)

This is the religion of Allah with which He sent His messengers and revealed His books. Whoever seeks anything else has, in fact, sought a religion other than Allah’s—namely Islam—about which He said: “Whoever seeks a religion other than Islam, it will never be accepted from him, and in the Hereafter he will be among the losers.” (3:85)