Musannaf Ibn Abi Shayba 37:584

Abdullah bin Bakr narrated to us, he said: Hatim bin Abi Saghirah narrated to us, from Amr bin Dinar, who said: When they mentioned regarding the affair of Uthman what they mentioned, Abd al-Rahman bin Awf approached with a group of his companions until they entered upon Abdullah bin Umar. They said: "O Abu Abd al-Rahman, do you not see what this man has brought about?" He said: "Bah, bah! So what do you command me? Do you want to be like the Romans and the Persians? If they became angry with a king, they would kill him. Allah has appointed him to that which He appointed him, and He is more knowing. I will not say anything regarding his affair."