Musannaf Ibn Abi Shayba 37:602

Abu Usama narrated to us, from Ibn Abi Arubah, from Qatadah, who said: Ali took Al-Ashtar by the hand, then he set off with him until he came to Talhah. He said: "Indeed, these people—meaning the people of Egypt—listen to you and obey you, so forbid them from killing Uthman." Talhah said: "I cannot repel blood that Allah has willed to be shed." So Ali took Al-Ashtar by the hand, then he turned away while he was saying: "How evil is what the son of Al-Hadramiyah thinks—that my cousin should be killed and he should overcome me regarding my authority. How evil is what I see."