From Sahih Muslim (Hadith 4743):
It has been reported on the authority of 'Adi b. 'Amira al-Kindi who said:I heard the Messenger of Allah (ﷺ) say: Whosoever from you is appointed by us to a position of authority and he conceals from us a needle or something smaller than that, it would be misappropriation (of public funds) and will (have to) produce it on the Day of Judgment. The narrator says: A dark-complexioned man from the Ansar stood up - I can visualise him still - and said: Messenger of Allah, take back from me your assignment. He said: What has happened to you? The man said: I have heard you say so and so. He said: I say that (even) now: Whosoever from you is appointed by us to a position of authority, he should bring everything, big or small, and whatever he is given therefrom he should take, and he should restrain himself from taking that which is forbidden
Reference: Muslim 4743