the Messenger of Allah—may Allah bless him and grant him peace—are confined to particular collections. Even supposing that all his hadiths were contained in such collections, a scholar does not know everything in the books; scarcely anyone could achieve that. Indeed, a man may possess numerous collections without knowing all their contents. Moreover, those who lived before these collections were compiled knew far more of the sunnah than later scholars, because much of what reached them and was established as authentic in their estimation may reach us only through an unknown narrator, or through a disconnected chain of transmission, or may never reach us at all. Their memories were their collections, containing many times what the written collections contain. No one acquainted with the matter doubts this.

Let no one say:

“Anyone who does not know all the hadiths is not qualified to exercise independent legal judgment.”

For if such qualification required knowledge of everything the Prophet—may Allah bless him and grant him peace—said and did concerning legal rulings, there would be no one in this community qualified to exercise independent legal judgment. The most a scholar can attain is knowledge of the greater part of that material, such that only a few details remain unknown to him. Yet he may take a position contrary to those few details that reach him.

The second reason:

The hadith may have reached him, but its authenticity was not established in his estimation. This may be because the person who related it to him, that person’s source, or another narrator in the chain was unknown to him, suspect, or had a poor memory. Alternatively, it may not have reached him with a complete chain, but rather with a disconnected one; or he may not have accurately retained its wording. Yet trustworthy narrators may have transmitted that same hadith to someone else through a connected chain: another scholar may know that a narrator unknown to him is trustworthy, or it may have been