Musannaf Ibn Abi Shayba 3:4104

Abu Bakr narrated to us, he said: Isma'il bin Ibrahim narrated to us, from Khalid al-Hadhdha', from 'Abd al-Rahman bin Sa'id bin Wahb, from his father, that 'Ali saw a people praying while they had let down their garments (sadlu). He said: "It is as if they are the Jews who have come out of their synagogues."