First: that this is what the Messenger brought.

Second: that whatever the Messenger brought must be followed. This second principle is a matter of faith; its opposite is disbelief or hypocrisy. Some groups among the speculative theologians, philosophers, rulers, and Sufis have fallen into aspects of this: by attributing some deficiency to the message, claiming some superiority over it, turning away from it outright, or holding that it is accepted only in matters subject to change, such as subsidiary rulings, but not in rational or political fundamentals—or through other positions that undermine faith in the message.

As for the first principle, it is a factual premise founded upon knowledge of chains of transmission and the texts themselves. This is the province of those versed in the Quran, the Sunnah, and consensus: their wording and meaning, their chains of transmission and their texts. Anything beyond these is either transmitted from the prophets or is not.

The former includes the Israelite traditions found among Muslims and the People of the Book, in which truth has become mixed with falsehood. The Prophet, may Allah bless him and grant him peace, said:

“When the People of the Book relate something to you, neither believe nor disbelieve them, for they may tell you something false and you believe it, or tell you something true and you disbelieve it.”

Nevertheless, such accounts may be heard and related when we know that they agree with what we already know, for they offer reassurance and are corroborated