Moreover, in Siyar Aʿlām al-Nubalāʾ al-Dhahabī devoted himself to every variety of critical analysis; he did not restrict his effort to a single sphere. He examined the people whose biographies he recorded, clarified their circumstances, issued historical judgments and evaluations, critiqued the sources from which he cited, drew attention to the slips of their authors, and excelled in grading hadith—both in their chains of transmission and their texts—applying the same standards to historical reports as well.

1 – Critiquing the Biographical Subjects
Al-Dhahabī’s assessment of a biographee generally consists of pronouncing a verdict on the person and stating his status, whether that be censure (jarḥ) or commendation (taʿdīl). He usually does so by quoting the views of reliable contemporaries, presenting their rulings on the individual and the personal impressions they formed through their acquaintance with him and their knowledge of his learning and conduct. In such cases al-Dhahabī may be content with their statements, refute them, or give preference to one opinion over another. The result of either endorsement or discredit is expressed in technical terms whose nuances are extremely precise, such as thiqah (reliable), ṣadūq (truthful), ṣuwayliḥ (somewhat righteous), dajjāl (charlatan), matrūk (abandoned), kadhdhāb (liar), majhūl (unknown), and the like—terms he explained in detail in the introduction to his valuable work Mīzān al-Iʿtidāl.

The primary purpose for which this critical method first arose was to make known the conditions of hadith transmitters so that sound Prophetic reports could be distinguished from unsound ones. Yet we find al-Dhahabī extending it, at the same time, to most of the figures he treats in this and his other books, even when they are not hadith specialists, indeed even to persons who have no connection with transmission in any form.

This led some of his contemporaries to object to the great attention he devoted to it, arguing that the motives which had prompted the early scholars to develop criticism were limited to authenticating the noble hadith, and that the hadith material had already become settled in the principal collections.