Musannaf Ibn Abi Shayba 3:1076

Abu Khalid narrated to us, from Mujalid, from al-Sha'bi and Zayd ibn Iyas, they said: Murrah ibn Sharahil narrated to us, he said: I was in a house in which were Abdullah ibn Mas'ud, Hudhayfah, and Abu Musa al-Ash'ari. The prayer time arrived, so this one said to that one, "Go forward," and that one said to this one, "Go forward." Then Abu Musa went forward, and Hudhayfah took him by his sides and pushed him forward. I said, "What is that for?" He said, "Because he witnessed Badr."