A person who finds a lost item is obligated to return it to its owner, as the verse states: “You shall not see your brother’s ox or his sheep wandering, and disregard them; you shall return them to your brother” (Deuteronomy 22:1). The ox and sheep mentioned here are merely examples; the commandment is to return any lost item of minimal value. The Sages clarified the ways in which one fulfills this mitzva.

Further reading: For a story of returning lost property involving Rabbi Ĥanina ben Dosa, see A Concise Guide to the Sages, p. 350.

If one knows who is the owner of an item that one has found, he is obligated to return it directly to him or to his home. If one does not know who the owner is, he must take an active role in looking for the owner by publicizing the item he has found. He should give only general information in his announcement, so that the owner can approach him and claim his loss by identifying it by its distinguishing characteristics. If the person who claims ownership over an item is only able to provide a general description (such as its color), that is insufficient, as it could easily be a guess while the item belongs to someone else. Knowledge of the precise location of the item is considered a distinguishing mark.

One who finds money in the street may take it for himself and does not need to publicize it or seek its owner. The reason for this is that the person who lost the money has presumably despaired of recovering it, as he knows that all banknotes and coins are essentially the same and he will be unable to provide distinguishing marks in order to claim it.

Even if there is a name or phone number on the lost bill, this is not a clear sign that it belongs to that person, as money passes from hand to hand and it is impossible to know if this information was written by the last owner.

However, if there is a clear distinguishing mark on an item that was found together with the money, one must publicize his finding and return the money to a person who can identify this distinguishing mark. For example, if money was found in an envelope that contains a clear mark, or if it is a bundle of bills or coins, and the claimant knows the exact amount, or if the notes are tied with a rubber band that has unique features, these are all considered identifying marks.

When a person finds money in a store and did not see who dropped it, then its status depends upon its location. If the money was found near the cash register or in another place where it can be presumed that it was dropped by the storekeeper, then it belongs to the store owner, and the finder must give the money to the person minding the store. If he found the money elsewhere in the store, he does not have to declare his finding, and may keep it for himself.

When one notices an item in a public place and it appears that it was not lost but placed there deliberately, he must leave the item in its place.

If the finder is uncertain as to whether the item was lost or intentionally placed there, and the item is in a secluded spot from where it is unlikely to be stolen, he should leave it where it is.

If one finds a lost item and he is embarrassed to carry it with him, because he is a distinguished individual or because he is unaccustomed to carrying such items in public, he must honestly answer the following question: What would he do if the item he has found was his own? If he would overcome the unpleasantness and take the item with him, he must act likewise in order to return another person’s possession. But if he would leave it in its place and move on without it, he is exempt from carrying the item to his home and from returning it to its owner.

If a person sees that another person’s property is being damaged (for example, it is on fire, being washed away in a flood, or being stolen by someone), he is obligated to try to rescue this property. This obligation also falls under the rubric of returning lost property.