—the proof be transmitted or rational; for rational evidence drawn from the Qur’an must be considered so long as it does not contradict what has been authentically transmitted. Without question, reason has a significant role in grasping the Qur’an. It is for this very purpose that Allah commands us to think about many of its noble verses; indeed, His words, “so that they may contemplate its verses” (Ṣād 38:29), explicitly encompass the intellectual reflection a person undertakes with his own mind.

The books written on tafsīr are crammed with both the worthless and the worthwhile, with blatant falsehood and manifest truth. Genuine knowledge is either a sound report transmitted from an infallible source, or a statement backed by an established proof. Anything beyond that is either forged and to be rejected, or left in abeyance—neither branded as counterfeit nor certified as sound.

Commentary
“True knowledge is either a sound report transmitted from an infallible source”—namely, the Messenger of Allah, peace and blessings be upon him—“or a statement supported by an established proof,” meaning a statement of one of the Companions, the Followers, or those after them that rests upon a recognized proof, whether rational or transmitted. For this reason we affirm the validity of analogy, which is a form of rational proof. Let this, then, serve as a guiding principle for identifying true knowledge: it is either a sound report from an infallible authority, or a statement founded on an established proof. Whatever falls outside these two categories is either spurious and must be rejected, or remains undecided—its status unknown, neither clearly bogus nor unquestionably accepted.