Abu Dawud Book 3, Hadith Number 1697.
Narated By Ubayy ibn Ka’b : Suwayd ibn Ghaflah said: I fought along with Zayd ibn Suhan and Sulayman ibn Rabi’ah. I found a whip. They said to me: Throw it away. I said: No; if I find its owner (I shall give it to him); if not, I shall use it. Then I performed hajj; and when I reached Medina, I asked Ubayy ibn Ka’b.
He said: I found a purse which contained one hundred dinars; so I came to the Prophet (PBUH). He said to me: Make the matter known for a year. I made it known for a year and then came to him. He then said to me: Make the matter known for a year. So I made it known for a year. I then (again) came to him. He said to me: Make the matter known for a year. Then I came to him and said: I did not find anyone who realises it. He said: Remember, its number, its container and its tie. If its owner comes, (give it to him), otherwise use it yourself.
He (the narrator Shu’bah) said: I do not know whether he said the word “make the matter known” three times or once.