Musannaf Ibn Abi Shayba 36:526

Waki’ narrated to us, from Isra’il, from Abu Ishaq, from ‘Amr ibn Maymun al-Awdi, that when ‘Umar ibn al-Khattab was dying, he said: "Call for me ‘Ali, Talhah, al-Zubayr, ‘Uthman, ‘Abd al-Rahman ibn ‘Awf, and Sa’d." He said: He did not speak to any of them except ‘Ali and ‘Uthman. He said: "O ‘Ali, perhaps these people know your kinship and what Allah has given you of knowledge and jurisprudence. Fear Allah, and if you are entrusted with this matter, do not raise the sons of so-and-so over the necks of the people." And he said to ‘Uthman: "O ‘Uthman, perhaps these people know your affinity to the Messenger of Allah (may Allah bless him and grant him peace), your age, and your honor. If you are entrusted with this matter, then fear Allah and do not raise the sons of so-and-so over the necks of the people." Then he said: "Call Suhayb for me." He said: "Lead the people in prayer for three days, and let this group gather and seclude themselves. If they agree upon a man, then strike the head of whoever opposes them."