Musannaf Ibn Abi Shayba 3:1978

Hushaym narrated to us, he said: Yunus informed us, he said: Bakr bin Abdullah al-Muzani informed us, from Safwan bin Muhriz, who said: While al-Ash'ari was delivering the sermon on Friday, he recited the final prostration of Surah al-Hajj. He said: He descended from the pulpit and prostrated, then he returned to his seat.