Musnad Ahmad 476:1

Abu Abd al-Rahman al-Muqri narrated to us, al-Mas'udi narrated to us, he said: Abu 'Amrah narrated to me, from his father, he said: "We came to the Messenger of Allah, may Allah bless him and grant him peace, and we were four men, and we had a horse with us. He gave each person among us one share, and he gave the horse two shares."