Musnad Ahmad 459:16

Hassan ibn Musa narrated to us, he said: Shayban narrated to us, from Yahya, from Muhammad ibn Ibrahim, from Khalid ibn Ma'dan, that he narrated to him, that Jubayr ibn Nufayr narrated to him, that al-Irbad narrated to him—and al-Irbad ibn Sariyah was one of the People of the Bench (Ahl al-Suffah)—he said: "The Messenger of Allah (may Allah bless him and grant him peace) used to pray for the first row three times, and for the second row once."