Are we always obligated to pick up and return every lost object? Must we always assist someone with his loads?
From a simple reading of the pesukim in the Torah (see Shemot 23:4-5; 22:1-4) we do not find any exclusions. The Sages in our Gemara, however, do distinguish between different cases. According to the Mishna (29b) if someone sees an object that he would not ordinarily pick up – even if it was his own – he is not obligated to pick it up in order to return it to another. The terminology used in the baraita to describe this is zaken ve-eino le-fi kevodo – an elderly person (or, perhaps, a scholar), for whom this object’s return is not in keeping with his dignity. At the same time, Rabba teaches that once someone touches an animal that was lost, he becomes obligated to return it in any case.
Rashi and the Rambam explain Rabba’s ruling as being based on the fact that by touching or hitting the animal, the finder has “begun” the mitzva and becomes obligated to complete it. The Rosh and the Ran disagree, arguing that this is a special halakha that is true only in the case of an animal, since by touching or hitting it the animal may become more confused. Someone who has effectively driven the lost animal further from its owner becomes obligated in ensuring its return.
To illustrate this law, the Gemara tells of Rabbi Yishmael be-Rabbi Yosei who was walking and met a man carrying wood. The man put down his load to rest, and then asked Rabbi Yishmael to assist him in reloading them (see 22:4). Rabbi Yishmael, who was a wealthy individual and did not ordinarily perform such tasks, asked him how much the wood was worth (it was half a zuz), and rather than assist him, purchased the wood from him. After Rabbi Yishmael made the wood hefker (having no use for it, he declared it to be ownerless), the man reclaimed it and again asked Rabbi Yishmael for assistance. Rabbi Yishmael again purchased it from him and declared it ownerless. Then the man reclaimed it and, again, asked Rabbi Yishmael to help him load it. Yet again, Rabbi Yishmael purchased it from him, but this time declared it ownerless for everyone in the world except for this individual.
To the Gemara’s objection that Rabbi Yishmael was not obligated to help this man in the first place, given our ruling that zaken ve-eino le-fi kevodo is free of such obligations, the Gemara responds that lifnim mi-shurat ha-din hu d’avad – that Rabbi Yishmael was going beyond the letter of the law in his behavior.