Reliability of His Ahadith
In hadith studies, ibn Isḥaq's hadith is generally thought to be "good" (ḥasan) (assuming an accurate and trustworthy isnad, or chain of transmission) and himself having a reputation of being "sincere" or "trustworthy" (ṣadūq). However, a general analysis of his isnads has given him the negative distinction of being a mudallis, meaning one who did not name his teacher, claiming instead to narrate directly from his teacher's teacher. Because of his tadlīs, many scholars including Muhammad al-Bukhari hardly ever used his narrations in their sahih books. According to al-Khaṭīb al-Baghdādī, all scholars of ahadith except one no longer rely on any of his narrations, although truth is not foreign to him. Others, like Ahmad ibn Hanbal, rejected his narrations on all matters related to fiqh. Al-Dhahabī concluded that despite his good qualities any narration solely transmitted through him should probably be considered as containing munkar.
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