They said about Imam al-Dhahabī:

1 – I found in him neither the rigidity typical of some ḥadīth specialists nor the dullness of mere transmitters. On the contrary, he is a jurist in his reasoning, well-versed in people’s statements, the legal opinions of the early Imams, and the doctrines of the various schools.

2 – What pleases me most in his writings is that he never cites a ḥadīth without clarifying any weakness in its text, obscurity in its chain of transmission, or criticism of its narrators. I have not seen anyone else observe this benefit in what they transmit.

Ṣalāḥ al-Ṣafadī (d. 764 AH)

3 – As for our teacher Abū ʿAbd-Allāh, his insight has no equal. He is a treasure to which one turns when a thorny problem arises, the unrivalled imam of the age in memorization, the gold of the era in both meaning and expression, the shaykh of al-jarḥ wa-l-taʿdīl (critique and validation of transmitters), and the foremost of men in every path. It is as though the whole ummah were gathered on a single plain, he surveyed them, and then reported about them as one who had been present among them.

Tāj al-Subkī (d. 771 AH)

4 – The great ḥāfiẓ, the historian of Islam, the shaykh of the ḥadīth scholars, and the seal of the masters of memorization.

Ibn Kathīr al-Dimashqī (d. 774 AH)

5 – In the study of ḥadīth—biographical evaluation and its other branches—the hadith scholars are all dependants of four figures: al-Mizzī, al-Dhahabī, al-ʿIrāqī, and Ibn Ḥajar.

Jalāl al-Dīn al-Suyūṭī (d. 911 AH)