Musannaf Ibn Abi Shayba 38:76

Ishaq ibn Sulayman narrated to us, he said: Abu Sinan narrated to us, from Amr ibn Murrah, who said: Sulayman ibn Surad came to Ali ibn Abi Talib after he had finished the fighting of the Day of the Camel, and he (Sulayman) had companionship with the Prophet, peace be upon him. Ali said to him: "You abandoned us, and you sat back from us, and you did so in front of the people." Sulayman met al-Hasan ibn Ali and said: "What I encountered from the Commander of the Faithful! He said to me such and such in front of the people." He (al-Hasan) said: "Do not let this frighten you from him, for he is a man at war. I saw him on the Day of the Camel, when the swords were taking their toll, saying: 'I wish I had died twenty years before this day.'"