Ahmad ibn Hanbal: I remember him with Amr ibn Abdullah, meaning ibn Abd Qays, and once: when he died, he said, may God have mercy on him and he has no equal in this nation except Amr ibn Abd Qays, for Amr died and left nothing and this one died and left nothing. Then he said, if he had married, his matter would have been complete.
Ahmad ibn Yahya ibn al-Jala': I saw Bishr ibn al-Harith and he had piety. It was said to him, to whom were you inclined? He said, Bishr ibn al-Harith is our teacher.
Ibrahim ibn Ishaq al-Harbi: From his horn to his foot he is filled with intellect, and al-Harbi did not narrate from him, and once: Baghdad did not bring forth a more complete intellect nor a more retentive tongue than Bishr ibn al-Harith. In every hair of his was intellect. He trod on the people's heels for fifty years, no backbiting of a Muslim was known from him. If his intellect were divided among the people of Baghdad, they would become intelligent, and nothing would be diminished from his intellect. And once: I did not see
Ibn Abi Hatim al-Razi: Trustworthy, pleasing
Ibn Hajar al-Asqalani: Trustworthy, exemplary, pious, great
Al-Khatib al-Baghdadi: He was among those who surpassed the people of his time in piety and asceticism. He was distinguished by the abundance of his intellect, the various virtues, the good approach, the uprightness of his doctrine, the nobility of his soul, and the abandonment of trivialities. He was a great narrator of hadith, but he did not devote himself to narration and hated it, and he buried his books for that reason, and all that is heard from him is only by way of reminder.
Al-Daraqutni: Trustworthy, ascetic, a mountain, he only narrates sound hadith, and sometimes the calamity is from those who narrate from him.
Ali ibn Khushram al-Marwazi: Bishr used to give fatwas in his early days and he was wounded.
Muslim ibn al-Qasim al-Andalusi: Trustworthy, excellent
Yahya ibn Aktham al-Qadi: We have not heard anything about Amr ibn Abd Qays except that there is something like it or more in Bishr ibn al-Harith, unless there was something in the heart of Amr that was not in the heart of Bishr.