English: “You shall not see your brother’s ox … and hide yourself” — one might think he may hide himself? The Torah therefore states [elsewhere] “you shall not be able to hide yourself.”
On the daf / in context: The Sages derive that the obligation to return a lost animal is absolute; one may not ignore it.
Type of Learning
Derash establishing the absolute nature of the mitzvah of returning lost property.
What Is Learned
One is not permitted to ignore a lost animal belonging to another; the obligation to return it is binding.