Ziyad bin Sa'd bin Dumayrah al-Sulami narrated to Urwah bin al-Zubayr from his father (may Allah be pleased with him) that Muhallim bin Jaththamah al-Laythi killed a man of Ashja' in (the time of) Islam. This was the first blood money that the Messenger of Allah (peace and blessings be upon him) decided. He (peace and blessings be upon him) said: "O Uyaynah, will you not accept the blood money?" The narrator said that at the end of it, the Messenger of Allah (peace and blessings be upon him) said: "Did you kill him with your weapon at the dawn of Islam?" Then he (peace and blessings be upon him) said in a loud voice: "O Allah, do not forgive Muhallim."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18271