One who robbed someone or stole something from him must return it to its owner, as it is written: “He shall restore the stolen item that he stole” (Leviticus 5:23).

If the item was lost, damaged, or irreversibly changed its form, the thief must pay the owner its full value, established at the time that he took it.

It is prohibited to buy a stolen item from a thief or robber, as by doing so, the buyer is only encouraging him to continue his criminal behavior. If one purchased a stolen item, and the owner has not lost all hope of restoring it to his possession, the buyer must return the item to its owner.

If one innocently bought an item without knowing that it was stolen, and the owner of the item demands that he return it to him, the owner must pay the buyer the price that the buyer paid the thief. The owner of the item is then entitled to sue the thief to reclaim this payment. This halakha, which is called takanat hashuk (a provision ensuring the integrity of the marketplace), was established by the Sages in order to protect blameless people who bought stolen property from being taking advantage of by thieves.

If the owner of the item had already despaired of recovering the stolen object, and it was given or sold to a third party who did not know that it was stolen, that third party is exempt from returning it to its original owner even in return for payment. The owner of the item may of course still sue the thief to recover its value.