Abu Ahmad al-Hakim: His hadith is not reliable.
Abu Ahmad ibn Adi al-Jurjani: The saying about him is what Shu'bah said, that there is nothing wrong with him.
Abu Bakr al-Bayhaqi: He is not to be used as a reference.
Abu Hatim al-Razi: His place is that of truthfulness, but he is not strong. His hadith should be written down, but not used as proof.
Abu Hatim ibn Habban al-Busti: I followed his hadith and found him to be truthful, but when he got old, his memory deteriorated, and errors appeared in his narrations, so he deserved to be abandoned.
Abu Hafs Umar ibn Shahin: It is necessary to pause regarding him, and he is in my opinion among the trustworthy.
Abu Zur'ah al-Razi: He is lenient, weak.
Abu Nu'aym al-Fadl ibn Dukin: It was said to him: Is there anything wrong with Qays ibn al-Rabi'? He said: No.
Ahmad ibn Hanbal: He was lenient. He said: He narrated rejected hadiths. And once: He used to make mistakes in hadith.
Ahmad ibn Shu'ayb al-Nasa'i: He is not trustworthy. And once: He is abandoned in hadith.
Ahmad ibn Salih al-Jili: He was truthful, but people abandoned his hadith.
Ibrahim ibn Ya'qub al-Jawzajani: He is mediocre.
Ibn Hajar al-'Asqalani: He was truthful, but his memory deteriorated in old age, and his son introduced narrations that were not his, and he narrated them.
Al-Daraqutni: He is weak in hadith.
Al-Dhahabi: One of the vessels of knowledge, truthful in himself, but with a bad memory.
Sufyan al-Thawri: He considered him trustworthy.
Sufyan ibn 'Uyaynah: I have not seen a man in Kufa with better hadith than him.
Sharik ibn 'Abd Allah al-Nakha'i: There was no one like him left after him. And once: No one who grew up in Kufa was more eager for hadith than Qays ibn al-Rabi'.
Shu'bah ibn al-Hajjaj: He is trustworthy. And he once said: Reach Qays before he dies.
Abd al-Rahman ibn Mahdi: He narrated from him then abandoned him.
Abd al-Rahman ibn Yahya al-Masri: The most knowledgeable of the people of Kufa in hadith.
Uthman ibn Abi Shaybah al-'Absi: Truthful, but some of his hadith is confused.
Uffan ibn Muslim al-Saffar: Trustworthy. And once: He criticized him.
Ali ibn al-Madini: He considered him very weak.
Muhammad ibn Isma'il al-Bukhari: I do not write down his hadith nor narrate from him.
Muhammad ibn Sa'd, the scribe of al-Waqidi: He narrated many hadiths, but he is weak in it.
Muhammad ibn 'Abd Allah al-Makhrami: There are mistakes in his hadith.
Muhammad ibn 'Abd Allah ibn Numayr: He had a son who was his downfall. The scholars of hadith looked into his books and rejected his hadith, thinking that his son had altered them.
Muhammad ibn 'Ubayd al-Tanafi: His situation remained upright until he died.
Muhammad ibn 'Umar al-Waqidi: A scholar of hadith.
Mu'adh ibn Mu'adh al-'Anbari: He used to praise him highly.
Hishām ibn 'Abd al-Malik al-Tūsī: Trustworthy, with good hadith.
Wakee' ibn al-Jarrah: He considered him weak.
Yahya ibn Sa'id al-Qattan: He used to disparage him and did not approve of him.
Yahya ibn Ma'in: He is nothing. And once: He is weak. And once: His hadith should not be written down. And once: He was a Shi'ite, and he made many mistakes, and he has rejected hadiths. And once, when he was asked about his downfall, he said: His downfall was his luck.
Ya'qub ibn Shaybah al-Sadusi: According to all of our companions, he is truthful, his book is good, but he has a very bad memory, he is confused, and makes many mistakes.