Sulaiman bin Musa said: I said to Imam Tawus (may Allah have mercy on him): So-and-so narrated such-and-such to me. He said: Your narrators (of hadith) are trustworthy, so take their narration.

Sa’d bin Ibrahim said: Only trustworthy narrators report hadith from the Messenger of Allah, peace and blessings be upon him.

Imam Muhammad bin Sirin, may Allah have mercy on him, said: In the beginning, people did not ask about the chain of narration, then they started asking (i.e., they began to inquire about who the narrator is and what he is like). If the narrator was a follower of the Sunnah, they would accept the hadith from him, and if he was not a follower of the Sunnah, they would not accept the hadith from him. Imam Darimi said: I do not think that Jarir heard this from Asim.

Imam Muhammad bin Sirin, may Allah have mercy on him, said: The hadith you narrated to me, do not narrate it through these two men anymore because they do not care from whom they are taking the hadith. Imam Darimi said: I am not certain that Jarir heard this from Asim.

Ibrahim Nakha'i, may Allah have mercy on him, said: When you narrate a hadith from me, narrate it through the way of Abu Zur'ah, may Allah have mercy on him, because he narrated a hadith to me, then after a year I asked him about the same hadith, and he had not omitted even a single letter from it.

Imam Muhammad bin Sirin, may Allah have mercy on him, said: This knowledge (Hadith) is religion, so a person should be careful from whom he is taking his religion.

Ibrahim al-Nakha'i, may Allah have mercy on him, said: (The righteous predecessors) when they went to someone to take knowledge of hadith, they would carefully observe his prayer, manner, and appearance. Then they would take hadith from him.

Ibrahim al-Nakha'i, may Allah have mercy on him, said: When they (i.e., the righteous predecessors) would come to a man from whom they wanted to take knowledge, they would observe his prayer, conduct, and appearance, then they would take knowledge from him.

Hasan al-Basri (may Allah have mercy on him) also narrated in the same manner as Ibrahim (may Allah have mercy on him).

Abu Al-Aliyah said: We used to go to a man to take narration from him, so when he prayed, we would observe him; if he performed the prayer properly, we would sit down and say, "He will be good in matters other than prayer as well." And if he did not perform the prayer properly, we would get up from him and say, "He will be even worse in matters other than prayer." Abu Muammar said: These are his exact words.