DEUT181 Do not covet what belongs to your fellow Jew. One should not wonder, “How can the Torah forbid us to have covetous thoughts when we see beautiful, attractive things in the possession of our neighbors?” Such a question assumes that one has no power over one's thoughts. In truth, a person can stop himself from covetous desire and only fools and people stooped in sin think otherwise. It certainly is within our capability to control our thoughts and wishes so that we do not desire everything that we see. It is simply a matter of willpower. Just as we can come to want something, we just as easily can make ourselves not want it and completely divorce ourselves from thinking about it. Not one of our thoughts, fixed or fleeting, is hidden from Hashem. Accordingly, if we transgress His Will by thinking thoughts that He forbids, He punishes us. On the other hand, for those who love Him and turn all of their thoughts towards perfecting how they serve Him, He sets aside unlimited amounts of kindness. Nothing is better for a person than a virtuous and pure thought, for such is the beginning and end of every good deed. About this mitzvah, our sages teach (Mechilta, Parashas Yisro, chap. 20), “Physical desire leads to coveting, and coveting leads to theft.” Key concept is obvious, for distancing us from theft benefits everyone. As soon as one permits oneself to harbor covetous thoughts for something that belongs to his fellow Jew, he violates this prohibition. His punishment is great, for coveting leads to several types of woe, as received from prophecy about the incident involving Achav and Navos [1 Kings 20-22—AJL].