Thus, whatever the messengers brought from Allah constitutes authority. The Quran (1) is an authority, and the sunnah is an authority. Yet it can be known that the Prophet—may Allah bless him and grant him peace—brought it only through truthful transmission from Allah. Therefore, anyone who adduces as evidence something transmitted from the Prophet—may Allah bless him and grant him peace—must ascertain its authenticity before believing what it entails and using it as evidence. If he adduces it as evidence against someone else, he must demonstrate its authenticity; otherwise, he will be speaking without knowledge and arguing without knowledge.

Since it is known that the books compiled on merits contain false reports, relying merely upon what they contain is like relying upon the testimony of a flagrantly sinful person, who sometimes speaks truthfully and at other times lies. Indeed, even if it were not known that they contained falsehoods, they would still afford us no knowledge until we know (2) that the person who transmitted them is trustworthy.

Hundreds of years (3) separate us from the Messenger, and we necessarily know that what people transmit from him and from others includes both truth and falsehood (4). It has been narrated from him that he said:

“Lies will be told about me.”

If this hadith is true, then lies will inevitably be told about him; and if it is false, then a lie has already been told about him. Since (5) this is so, no one may adduce a hadith as evidence concerning a subsidiary issue until he demonstrates the grounds upon which its authenticity is established. How, then, can someone adduce it as evidence in matters of fundamental doctrine, thereby impugning the best generations, the great majority of Muslims, and the foremost saints of Allah who have been brought near to Him, when the person citing it does not even know whether it is true?