Sayyiduna Suwayd bin Ghafalah (may Allah have mercy on him) said: I went out with Zayd bin Suhan and Salman bin Rabi'ah (may Allah be pleased with them both), and I picked up a whip at a place called al-Udhayb. The two of them said: Leave it. I said: By Allah! I will not leave it; wild animals would eat it. I will make use of it. I went to Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) and mentioned this to him, and he said: You did well, you did well. In the time of the Messenger of Allah (peace and blessings be upon him) I found a purse containing a hundred dinars. I went to the Prophet (peace and blessings be upon him) and he (peace and blessings be upon him) said: "Announce it for a year." I announced it for a year, then I came to the Messenger of Allah (peace and blessings be upon him) and he (peace and blessings be upon him) said again: "Announce it for another year." When I came after three times, he (peace and blessings be upon him) said: "Know its number and its tie well. If someone comes and tells you its number and also its tie, then give it to him; otherwise make use of it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12081