Sahih al-Bukhari 2372

It is related that Zayd ibn Khalid said, "A man came to the Messenger of Allah, may Allah bless him and grant him peace, and asked him about finding some lost property. The Prophet, may Allah bless him and grant him peace, said, 'Note the details of its container and its binding and publicise it for a year. If its owner comes, (give it to him). Otherwise, do what you want with it.' He said, 'What about a lost sheep?' and he said, 'It is for you, your brother or the wolf.' Then he said, 'What about a lost camel?' and he said, 'It has nothing to do with you. It has its water and its feet and it will find water and graze from the trees until its owner finds it.'"