Musnad Ahmad 32:690

Abu Kamil and ‘Affan narrated to us, they said: Hammad narrated to us, from Thabit al-Bunani. ‘Affan said in his narration: Thabit informed us, from Anas ibn Malik, who said: "The night prayer (Isha) was called—‘Affan said in his narration: The latter one—one night. A man stood up and said: 'O Messenger of Allah, I have a need of you.' So he stood with him, speaking privately to him, until the people—or he said: some of the people—became drowsy. Then he prayed, and he did not mention ablution."