—much less those who have not devoted themselves to it—for it demands wide-ranging acquaintance with the prophetic reports, their transmission-paths, their exact wording, and the specific passages that constitute proof. In many cases the modern indexes of hadith cross-references are of little help; what really counts is the knowledge that settles into the mind of a person who has grappled with this discipline for a long time.

The one who explained this rule most persuasively, supporting it with the learning Allah had granted him, is Shaykh al-Islam Ibn Taymiyyah—may Allah have mercy on him—in Majmuʿ al-Fatāwā, 18/25-26. I have cited his words in my book Al-Radd al-Mufḥim, which I ask Allah to enable me to revise and publish. He said:

“In the scholars’ terminology weak reports are of two kinds.

1. A weak report whose weakness does not prevent acting upon it; this is akin to what al-Tirmidhi calls ḥasan (fair).
2. A weak report whose weakness obliges one to leave it; this is the wāhi (feeble) type.

Sometimes a transmitter is deemed weak because he frequently errs, yet the majority of his narrations are actually sound. In such a case they record his reports for the purpose of comparison and corroboration, for multiple chains—when plentiful—reinforce one another until they may yield knowledge, even if the transmitters were immoral sinners; so how much more so when they are learned and upright but prone to numerous mistakes! A case in point is ʿAbd Allah ibn Lahīʿah. He was one of the eminent scholars of the Muslims and served as a judge in Egypt, transmitting a large body of hadith. When his books were destroyed by fire he began narrating from memory, and many errors crept into his reports, though the majority of what he related remained sound. Aḥmad said: ‘I may write down a man’s hadith for purposes of comparison, just as I do with Ibn Lahīʿah.’”