Deuteronomy 22:3 In like manner shalt thou do with his ass; and so shalt thou do with his raiment; and with all lost thing of thy brother’s, which he hath lost, and thou hast found, shalt thou do likewise: thou mayest not hide thyself.
If you find something that your brother has lost then give it back to him. That was the rule for those living in Israel. They had to take care of each other. They were watching each other’s back. If you left it or lost it your neighbor was to get it to you.
If you found something then it was your responsibility to see about getting it back to its rightful owner. They were never to take advantage of their neighbor’s mistake or loss.
This isn’t written for us but the principle should certainly apply. Do good to others. Help instead of taking advantage.