Musnad Ahmad 1153:580

Sakan ibn Nafi’ narrated to us, he said: Salih ibn Abi al-Akhdar narrated to us, from al-Zuhri, from ‘Urwah, from ‘Aishah, that the Messenger of Allah, peace and blessings of Allah be upon him, said: "Whoever has a kindness done to him, let him recompense it. And whoever is not able to, let him mention it; for whoever mentions it, he has thanked him. And whoever claims to possess what he has not attained, he is like one who wears two garments of falsehood."