Musannaf Ibn Abi Shayba 36:544

Abu Usama narrated to us, from Kahmas, from Abdullah ibn Shaqiq, who said: Haram ibn al-Harith and Usama ibn Harim narrated to me—and they were both companions in military expeditions—and they both narrated it to me, and neither of them was aware that his companion had narrated it to me, from Murra al-Bahzi, who said: While we were with the Messenger of Allah (may Allah bless him and grant him peace) one day on one of the paths of Medina, he said: "What will you do during a tribulation that rises in the regions of the earth as if it were the horns of cattle?" They said: "What should we do, O Prophet of Allah?" He said: "You must follow this one and his companions." He said: So I hurried until I turned toward the man and said: "This one, O Prophet of Allah?" He said: "This one." And behold, it was Uthman.