Musnad Ahmad 30:3520

Aswad ibn Amir narrated to us, Abu Bakr ibn Ayyash informed us, from al-A’mash, from Abu Hazim, from Abu Hurairah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever asks you by Allah, then give him. And whoever invites you, then answer him. If a sheep’s trotter were gifted to me, I would accept it, and if I were invited to a sheep’s trotter, I would answer."