Musnad Ahmad 28:371

Abu al-Nadr narrated to us, Ishaq bin Sa'id narrated to me, Sa'id bin 'Amr narrated to us, from 'Abdullah bin 'Amr, who said: I bear witness by Allah that I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "He will make it lawful, and a man from Quraysh will make it lawful through him. If his sins were weighed against the sins of the two heavy ones (mankind and jinn), they would outweigh them."