Sahih al-Bukhari 2426

Adam narrated to us: Shu'ba narrated to us. Muhammad ibn Bashshar also told me: Ghundar narrated to us: Shu'ba narrated to us, from Salama, who said: I heard Suwayd ibn Ghafala say: I met Ubayy ibn Ka'b (may Allah be pleased with him). He said: I found a purse containing one hundred dinars and brought it to the Prophet (peace and blessings be upon him). He said, ‘Announce it for a year.’ I did so, but found no one who recognized it. Then I came back to him, and he said, ‘Announce it for a year.’ I did so and found no one. I came back to him a third time, and he said, ‘Remember its container, its number, and its tie. If its owner comes, return it to him; otherwise, make use of it.’ I made use of it. Later I met him in Mecca, and he said, ‘I do not know whether it was three years or one year.’