Musnad Abu Ya'la al-Mawsili 117:53

Hadaba narrated to us, Sulayman ibn al-Mughirah narrated to us, from Thabit, who said: I said to Anas, "Narrate to me something of these wonders that no one else narrates." He said: The Messenger of Allah (ﷺ) prayed Dhuhr one day in Medina, then he came to the seats upon which Gabriel used to come to him, and he sat upon them. Bilal came and called for Asr. Those who had families in Medina stood up to perform ablution and attend to their needs. There remained men from the Emigrants (Muhajirun) who had no families in Medina. A vessel—meaning a shallow one—containing water was brought to the Messenger of Allah (ﷺ). He placed his fingers into the vessel, but it could not contain all his fingers, so he placed these four. He said, "Come forward and perform ablution." So they all performed ablution. I said to Anas, "How many do you think they were?" He said, "Between seventy and eighty."