1118 - Ahmad ibn Muhammad narrated to us, he said: Abu al-Nu'man narrated to us, he said: Khalid ibn al-Harith narrated to us, he said: I heard 'Ubaydullah ibn al-Hasan being asked about a Jew who led a people in prayer while they were unaware. He considered his praying with them as [an act of] a Muslim, and if he refused [to accept Islam], he is to be asked to repent. He used as evidence for this his statement: "Whoever prays our prayer..." He was asked about his praying with them while he was in a state of major ritual impurity (junub) or without wudu? He was of the opinion that their prayer is valid, and he used the statement of 'Umar (may Allah be pleased with him) as evidence.

Chapter: Prayer behind the Qadariyyah and others among the people of innovation (Ahl al-Bid'ah)

• I asked Ishaq about praying behind the Qadariyyah? He said: "Do not pray behind him intentionally while you know he is a Qadari. If you have prayed [behind him without knowing], it is permissible, and you do not have to repeat it," meaning: if you did not know.

1119 - Ahmad ibn Yunus narrated to us, he said: I heard a man say to Sufyan al-Thawri: "A man denies the Qadar (divine decree); should I pray behind him?" He said: "Do not put him forward [as an Imam]." He said: "He is the Imam of the village; they have no other Imam?" He said: "Do not put him forward, do not put him forward."

1120 - Sahl ibn Muhammad narrated to us, he said: al-Asma'i narrated to us, he said: 'Umar ibn al-Haytham narrated to me, he said: It was said to al-Thawri: "What do you say about a man who prayed behind a Qadari?" He said: "Repeat it, even if [it has been] four years."

1121 - Muhammad ibn al-Wazir narrated to us, he said: Marwan narrated to us, he said: Al-Awza'i said: "Do not pray behind a Qadari, unless you are compelled."