Sahih al-Bukhari 2426
صحيح البخاري#2426SahihNarrated Ubai bin Ka`b:I found a purse containing one hundred Diners. So I went to the Prophet (and informed him about it), he said, "Make public announcement about it for one year" I did so, but nobody turned up to claim it, so I again went to the Prophet (ﷺ) who said, "Make public announcement for another year." I did, but none turned up to claim it. I went to him for the third time and he said, "Keep the container and the string which is used for its tying and count the money it contains and if its owner comes, give it to him; otherwise, utilize it." The sub-narrator Salama said, "I met him (Suwaid, another sub-narrator) in Mecca and he said, 'I don't know whether Ubai made the announcement for three years or just one year
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 45:1