Bava Metzia 23 - 29
Rava said, “The obligation to return a lost object to a person who claims and describes the object that he lost with proper ‘signs’ is a Torah obligation.”
There is both a positive mitzvah and a “negative command” to return a lost object to its owner, as the verses state, “You shall return it to him” and “You shall not ignore it”. (See Devarim 22:1-3)
The gemara asks if the obligation to return the lost object based on simanim (signs that identify the object) is of Torah origin or is a Rabbinical decree. Rava explains that it is of Torah origin since there is a verse that teaches to return the lost object to one who gives proper signs: “It shall be with you until your fellow person seeks it out” (Dev. 22:2). “Would I ever think to return it to someone who doesn’t seek it out?” asks Rava rhetorically. Rather, the words in the verse “ad drosh achicha oto” need to be understand in a manner that is different than at first glance. The intent of these words is that the finder “seeks out and checks out” the person who claims he lost it, by demanding proper identification of the object. In this way the finder is certain that he is not giving the lost object to a fraud, but that in fact he is returning the lost object to its true owner.
- Bava Metzia 28a