It is narrated from Mukhariq bin Sulaym that he said: On the day of the Battle of the Camel I was walking alongside Sayyiduna Ammar bin Yasir (may Allah be pleased with him). Hanging from his saddle was a horn (vessel) in which he would urinate when he needed to. When the time for fighting drew near, he said: "O Mukhariq! Go to the banner of your people." I said: "I am not going to leave you while I am in this state today." He said: "No, O Mukhariq! Go to the banner of your people, for I saw that the Messenger of Allah (peace and blessings be upon him) liked a man to fight under the banner of his own people." This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.