Musannaf Ibn Abi Shayba 3:2807

Ibn Idris narrated to us, from Husayn, from Salim, from Jabir, who said: A caravan with merchandise arrived on the day of Friday while the Messenger of Allah was delivering the sermon. The people turned away to look at it, and there remained with the Messenger of Allah twelve men. Then this verse was revealed: "And when they see a transaction or a diversion, they disperse to it and leave you standing."