Q: What is the source of the mitzvah of hashavas aveidah, returning lost property?

A: When we encounter a lost item, there is a mitzvah to safeguard it and attempt to return it to its owner:

“You shall not see the ox of your brother or his sheep or goat cast off, and hide yourself from them; you shall surely return them to your brother. If your brother is not near you and you do not know him, then gather it inside your house, and it shall remain with you until your brother inquires after it, and you return it to him…. So shall you do for any lost article of your brother that may become lost from him and you find it; you shall not hide yourself (Devarim 22:1-3).”

The primary mitzvah is the positive command: “Hashev teshivem” — return them, and there is an added prohibition not to ignore a lost item, “Lo suchal l’hisalem” — You shall not hide yourself (B.M. 26b). If a person unlawfully takes a lost item for himself, he also violates the prohibition, “Lo sigzol” — Do not steal (Vayikra 19:13).

B’ezras Hashem, we will explore the details of hashavas aveidah in the coming series.