Musannaf Ibn Abi Shayba 13:3016

Abu Bakr narrated to us, he said: Muhammad ibn Bishr al-'Abdi narrated to us, he said: Muhammad ibn 'Amr narrated to us, he said: Abu Salamah narrated to us, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "I am only a human being, and it may be that some of you are more eloquent in their argument than others. So, whoever I judge in his favor regarding the right of his brother, then I have only cut out for him a piece of the Fire."