Exodus 23:4

23:4 “If you encounter your enemy’s ox or donkey wandering off, you must by all means return it to him.

Deuteronomy 22:1-3

Laws Concerning Preservation of Life

22:1 When you see your neighbor’s ox or sheep going astray, do not ignore it; you must return it without fail to your neighbor. 22:2 If the owner does not live near you or you do not know who the owner is, then you must corral the animal at your house and let it stay with you until the owner looks for it; then you must return it to him. 22:3 You shall do the same to his donkey, his clothes, or anything else your neighbor has lost and you have found; you must not refuse to get involved.