Musannaf Ibn Abi Shayba 13:2282

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Ibn Abi Dhi’b narrated to us, from al-Zuhri, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Three are Sunnah, upon them is their reward," meaning from the great ones: The *manihah* (loaning of a milk-producing animal), the *udhiyah* (sacrificial animal), and a man performing Hajj on behalf of a man who has never performed Hajj at all.