Musannaf Ibn Abi Shayba 18:1009

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Jarir ibn al-Sa’ib narrated to us, from al-Hasan, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I did not contend with my Lord regarding anything as I contended with Him regarding the killer of a believer, but He did not answer me."