Kulthum (may Allah have mercy on him) said: I was in Wasit al-Qasab with Abd al-A'la bin Abdullah bin Amir when the doorkeeper said: This is Abu Ghadiyah al-Juhani. Abd al-A'la said: Bring him in. So he entered, wearing short (cut) garments; he was a tall, lean man, as if he were not from this Ummah. When he sat down, he said: I pledged allegiance to the Messenger of Allah (peace and blessings be upon him). I asked: With your right hand? He said: Yes. He (peace and blessings be upon him) addressed us on the day of al-Aqabah and said: "O people! Listen, your blood and your wealth are sacred to you, just as this day of yours is sacred, in this month of yours, in this city of yours. Listen, have I conveyed?" The people said: Yes. He (peace and blessings be upon him) said: "O Allah, bear witness." Then he said: "Do not become disbelievers after me, striking one another's necks." He said: We used to count Ammar bin Yasir (may Allah be pleased with him) among the best of us. He said: When it was the day of Siffin, he came walking on foot at the front of the army, until, when he was between the two ranks, he struck a man in his knee with a spear; he fell and his helmet came off, so I struck him, and behold, it was the head of Ammar (may Allah be pleased with him). (The narrator) said: A freed slave of ours began saying: "Which hand found it sufficient for him?" He said: I have not seen a man in more manifest misguidance than him, that he heard from the Prophet (peace and blessings be upon him) what he heard and then killed Ammar (may Allah be pleased with him).
Hadith Referenceالمعجم الكبير للطبراني / مسند من يعرف بالكنى / 19115
Abdullah bin Kulthum bin Jabr (may Allah have mercy on him) said: I heard my father say: We were with Anbasah bin Sa'id. One day I went to al-Hajjaj, and a man called Abu Ghadiyah al-Juhani came to him. Abd al-A'la bin Abdullah said: Go to him, help him dismount and say: Go back now. So we went out to him and said to him: Go back now. He dismounted, and Abd al-A'la went in and asked for water. Water was brought to him in a glass cup, but he refused to drink from glass; then it was brought to him in a wooden cup and he drank. Then he said: I pledged allegiance to the Messenger of Allah (peace and blessings be upon him) while I was returning the wealth of my family. Rashid bin Abyad, who was with me at Abd al-A'la's, said: With this right hand of yours? Abd al-A'la rebuked him and said: Let them divide it between themselves regarding him. He said: And I heard his sermon on the day of al-Aqabah, while he was saying: "Your blood and your wealth are sacred to you, just as this day of yours is sacred, in this month of yours, in this city of yours. Listen, do not become disbelievers after me, striking one another's necks." Then, on the day Sayyiduna Uthman (may Allah be pleased with him) was besieged, I heard a man saying: "Listen, do not kill this one." I looked at him, and it was Ammar (may Allah be pleased with him). Had it not been for his companions behind him, I would have trampled his belly. I said: O Allah, if You will, bring me face to face with him. Then when the day of Siffin came, suddenly I saw an evil man leading an army on foot. I looked at the armour and it had slipped off his knee, so I struck him with a spear, and behold, it was Ammar (may Allah be pleased with him).
Hadith Referenceالمعجم الكبير للطبراني / مسند من يعرف بالكنى / 19116