12.3 The One Whose Narration Is Accepted And The One Whose Narration Is Not Accepted And The Exposition Of (the Science Of) Invalidation And Attestation Of Reliability (al-jarh Wa Ta'dīl)
and dābit (accurate) in that which he narrates. As for the ‘adil, it is the Muslim, mature, sane person who is free from the causes of fisq (transgression) and doubt in his piety. As for the dābit, he is the one who is aware and not forgetful; a memoriser of his narration if he narrates from memory, and accurate in his transcription if he narrates from a book, and knowledgeable of the meaning of what he transmits and of what will change the intended meaning if he narrates by meaning.
The adālah (trustworthiness) of a narrator is established by his becoming known with good and the praise given to him; so whoever becomes well known for his trustworthiness amongst the people of transmission and their like from the people of knowledge and praise for his reliability and trustworthiness become widely known, this suffices him from needing any testimonial proof of his adālah (trustworthiness). The adālah of a transmitter is established likewise by the attestation (ta’dīl) of the imams or by one of them if his trustworthiness and scholarly approval of him is not well known.
A transmitter’s accuracy (dabt) is known by comparing his narrations with that of the reliable (thiqāt) narrators who are known for their accuracy and precision. If his narrations are found to be in accord with their narration even if (only) in meaning or they are in accordance in the majority of cases and divergences are rare then his accuracy is established.