Musnad Ahmad

It is narrated from Kulthum bin Habr that once we were sitting with Abdul A'la bin Amir in the city of Wasit, when a man present there, whose name was Abu Ghadiyah, asked for water. So, water was brought in a silver vessel, but he refused to drink that water and, mentioning the Prophet (peace be upon him), narrated this hadith: "Do not become disbelievers or misguided after me, striking each other's necks." Suddenly, a man began to abuse another. I said, "By Allah! If Allah grants me power over you in the army (I will settle the account with you)." Coincidentally, during the Battle of Siffin, I came face to face with him. He was wearing armor, but I recognized him through the gaps in the armor. So, I struck him with a spear and killed him. Later, I found out that he was none other than Sayyiduna Ammar bin Yasir. So, I regretfully said, "What kind of hands are these that express dislike for drinking water from a silver vessel, while these very hands have martyred Sayyiduna Ammar?"