Musnad Abu Ya'la al-Mawsili 3:9

Abu Khaythama narrated to us, Waki' narrated to us, Sayf al-Makki narrated to us, from Mujahid, from 'Abd al-Rahman ibn Abi Layla, from 'Ali: That the Prophet (may Allah bless him and grant him peace), when he slaughtered the sacrificial camels, commanded me to give away their meat, their hides, and their coverings as charity.