Muwatta Malik: Book 20, Hadith 243

Yahya related to me from Malik from Abd al-Malik ibn Qurayr from Muhammad ibn Sirin that a man came to Umar ibn al-Khattab and said, “I was racing a friend on horseback towards a narrow mountain trail and we killed a gazelle accidently and we were in ihram. What is your opinion?” Umar said to a man by his side, “Come, so that you and I may make an assessment.” They decided on a female goat for him, and the man turned away saying, “This amir al-muminin cannot even make an assessment in the case of a gazelle until he calls a man to decide with him.” Umar overheard the man’s words and called him and asked him, “Do you recite surat al-Ma’ida?” and he said, “No.” He said, “Then do you recognize this man who has taken the decision with me?” and he said, “No.” He said, “If you had told me that you did recite surat al-Ma’ida, I would have dealt you a blow.” Then he said, “Allah the Blessed, the Exalted says in His Book, ‘as shall be judged by two men of justice among you, a sacrificial animal to reach the Kaba’ (Sura 5 ayat 95), and this is Abd ar-Rahman ibn Awf.”