Musannaf Ibn Abi Shayba 34:288

Al-Fadl narrated to us, Abu Isra’il narrated to us, he said: Some of our companions informed me that Talhah was the first to pledge allegiance to Ali. A Bedouin saw him and said, "A matter that will not be completed." I said to Abu Isra’il, "Because of what?" He said, "Because of the state of his hand."