In this week's Torah reading, Mishpatim, we find a verse (Shmot 22:8) that explains the laws of a gusrdian that doesn't want to return the object he received to guard. The Torrah details certain objects to return and the Talmud explains why did the Torah identify those objects. There is a spiritual lesson on each one of them.
Based on Likutei Sihot, vol. 1, p. 155