The Tenth Commandment is somewhat difficult — it tells us not to envy somebody else. Most other commandments involve control or regulation of actual physical acts — this one encroaches on our very thoughts.

There are three categories of expression — thought, speech and deed. In Jewish tradition, controlling one's actions is the simplest level of self-control and observance. Speech is a little harder. Thought, such an internal, personal level of expression, is the hardest of all.

In Chassidic philosophy great emphasis is placed on the mind — the intellect — ruling over the heart — the emotions. By giving us this Commandment, G‑d is telling us that yes, we can control our very thoughts and direct them for good purposes. We are given the gift of human intelligence in order to be able to sift out the good from the bad, even deep in our own thoughts. By doing so, we are utilizing the advantage of human intelligence toward the true positive, constructive goals for which it was intended.

We hear a lot about "doing good deeds," which is definitely to be encouraged. However, the highest level of personal refinement, of character development, is when that same noble, principled action is not just an external action which may not reflect our true intention or desire, but when we are thinking along the same lines as our actions. It takes time, effort and refinement — but it is can be achieved.