Ziyad bin Sa'd bin Dumayrah al-Sulami relates, through Urwah bin al-Zubayr, from his father (Sayyiduna al-Zubayr bin al-Awwam (may Allah be pleased with him)), that Muhallim bin Jaththamah al-Laythi killed a man of the tribe of Ashja' in the early days of Islam, and this was the first case of blood-money that the Messenger of Allah (peace and blessings be upon him) decided. The narrator said: Uyaynah bin Badr spoke about the killing of the Ashja'i because he was from the tribe of Ghatafan, and al-Aqra' bin Habis spoke in defence of Muhallim bin Jaththamah because he was from the tribe of Khindif. The narrator said: At this the voices rose, and the quarrelling and clamour increased. The Messenger of Allah (peace and blessings be upon him) said: "O Uyaynah, will you not accept the blood-money?" He said: No, by Allah, not until I bring upon his women the same ruin and grief that he has brought upon my women. He said this two or three times, until a man from Banu Layth called Mukaytil stood up with a shield in his hand and said: O Messenger of Allah, for what this man did in the early days of Islam I find no likeness except sheep that came down to water: the first of them was shot, so the rest of them ran off. So make it a law today and change it tomorrow. The Messenger of Allah (peace and blessings be upon him) said: "Fifty now, and fifty more when we arrive back." And this happened on one of his journeys. Muhallim was a slender, tall, brown-complexioned man, and he was sitting at the edge of the people. The narrator said: The people kept urging him until he got up and sat in front of the Messenger of Allah (peace and blessings be upon him) with tears flowing from his eyes. He said: O Messenger of Allah, the matter that reached you has indeed happened, and I repent to Allah, the Mighty and Majestic, so pray for forgiveness for me. The Messenger of Allah (peace and blessings be upon him) said: "You killed him with your weapon in the early days of Islam. O Allah, do not forgive Muhallim." He said this three times in a loud voice, each time saying: "You killed him with your weapon in the early days of Islam. O Allah, do not forgive Muhallim."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5436