There is a Torah mitzva to have compassion for animals and not cause them suffering. Therefore, one who sees a donkey that has collapsed under the weight of its burden is commanded to help unload it so that it can stand, as the Torah states (Shemot 23:5): “If you see the donkey of your enemy lying under its burden, and you would refrain from helping him, you must surely help him.” In other words, even if one sees the donkey of someone with whom he is in conflict and feels inclined not to help, he must overcome that impulse and help. There are two reasons for this. First, one may not refrain from helping a person with whom one is in conflict. Second, one must relieve the suffering of the donkey that has collapsed under its heavy load (Bava Metzia 32b).
Because unloading fulfills the mitzva of tza’ar ba’alei ḥayim, one who sees a collapsed donkey must help unload it without expecting payment. Helping to load, by contrast, carries no such obligation: as with other labor, one is not required to work for another person without compensation. Even when unloading, if helping requires one to stop working, he may ask to be paid for the loss he incurs by interrupting his work (Rosh; Rema ḤM 272:6; Sema 272:9). According to some authorities, however, since the animal is suffering, he must stop and help even if he will not be compensated (Ran).
Because relieving the donkey’s suffering is one purpose of the mitzva, unloading takes precedence over loading. Thus, if two donkey owners need help – one to load his donkey and the other to unload a burden that has caused his donkey to collapse – one should first help unload the burden and relieve the donkey’s suffering. However, if the donkey that needs loading belongs to someone with whom one has a conflict that has reached the point of hatred, one should first help load that individual’s donkey. The goal is to subdue the evil inclination that led to hatred; perhaps through this they will return to loving one another (Bava Metzia 32b; SA ḤM 272:10).
If the person who sees the donkey lying under its burden is a distinguished person who is not accustomed to unloading donkeys in the street, he is not obligated to help unload it. His dignity takes precedence, and therefore there is no mitzva requiring him to forgo his honor in order to prevent the donkey’s suffering. Nevertheless, if he does forgo his honor and helps the donkey, he has performed a mitzva. A Torah scholar of public stature, however, is in a different position: his standing reflects on the Torah itself, and he may not act in a way that diminishes the honor of the Torah. If he wishes to help, he should hire someone else to unload the donkey (Rosh; Rema; AHS ḤM 263:4). Others maintain that a Torah scholar who conducts himself with extra piety and is not concerned for his own honor may help unload the donkey himself (Rambam and SA 272:3).
Sefer Ḥasidim (§44, §666, §668) writes that those who mistreat their donkeys by overloading them and then physically abusing the donkey when it is unable to walk, as well as those who kick their horses excessively when riding them, will ultimately face divine judgment for their cruelty. A light blow that gets an animal moving, however, is permitted, since this is how one urges it to do its work. We find the same idea when God was angry with Bilam for striking his donkey for no reason, as it is stated (Bamidbar 22:32): “Why did you strike your donkey?” Since Bilam knew that his donkey always obeyed him, he should not have struck it after it lay down; he should have understood that something was apparently preventing it from continuing. Because he acted cruelly and threatened it, “If I had a sword in my hand, I would kill you now,” he was punished measure for measure and killed by the sword.
