The focal point of Parshas Yisro is the 'Aseres HaDib'rot, the Ten Commandments, which form the introductory mitzvot stated directly by G-d in the presence of all of Israel, and, in the view of many Rishonim, include within them the concepts expressed in the entire list of 613 commandments. One would expect that the 'Aseres HaDib'rot should begin as well as end with fundamental principles of our obligations toward HaKadosh Boruch Hu. The conclusion with the prohibition of Lo Tachmod - not coveting another's material possessions - requires explanation as to its central nature. (See Rav Rosensweig's eye-opening analysis of this same question - Lo Tachmod: The Perfect Culmination of the Asseret ha-Dibrot. Here, we attempt an additional approach.)
Warning against desiring another person's possessions, the Torah first states not to covet another's house (Lo sachmod beis rei'echa). It then prohibits desiring specific people or possessions related to one's neighbor and lists together another's wife, servants, ox and donkey (Lo sachmod eishes rei'echa v'avdo va'amaso v'shoro vachamoro v'chol 'asher l'rei'echa). In explanation of this curious equivalence, Rav Zev Leff shlita, in a recent lecture, suggested that the root of coveting another's assets is a lack of satisfaction with one's own lot in life. "If only I were that other person," reasons the coveter, "I would have happiness!" Hence, all of that person's relationships and assets are equated since the coveter wants to be that person rather than desiring a specific one of his items. Perhaps this is the reason that the Torah begins by warning against coveting another's house followed by a second warning concerning specific items: it is the desire to be another person in general - to have his household - that leads to coveting his specific possessions.
The Torah demands of us through this commandment and related mitzvot to control our emotions. Although, formally, one only violates this prohibition if one actually seizes or at least pressures the original owner to forfeit or sell the item (see Rambam Hilchos Gezeila 1:9-10), the related prohibition Lo Sis'aveh (appearing in the 'Aseres HaDib'rot in Parshas Va'Etchanan) prohibits even plotting to do so. Envy over another's property without a plan to procure it through pressure or even theft, although not prohibited by these negative commandments, is sometimes forbidden by the commandment of v'Ahavta l'rei'acha kamocha (see Ramban K'doshim 19:18) and sometimes demonstrates a lack of middos perfection commanded by the mitzva of v'halachta bidrachav. (A full analysis of the scope of the prohibitions against envy and coveting is beyond the scope of this article. See L'reiacha Kamocha (vol. 1 - first section Lo Tachmod) by R. Dovid Ariav for additional sources.) What can prevent the temptation to be jealous of or even to covet another's possessions especially if one's own assets are meager? (See Ibn Ezra and L'rei'ach Kamocha Chapter 6.)
Every individual's true sense of identity is ultimately rooted in his soul. The pairing of a specific soul with its unique personality into a specific body which is determined at or soon before conception (see Nidda (16b) and Midrash Tanchuma Parashas P'kudei 3) is decided upon with great precision by HaKadosh Baruch Hu. It is this union which determines major aspects of a person's life since his body's genetic makeup will determine many of his physical qualities, some aspects of his personality, and many aspects of his health. The family in which he is born will greatly impact on his education, his training, his early social environment, will further affect his personality development, and often will even largely determine his career and marriage partner. Most of these factors, according the the Midrash Tanchuma, are determined by Hashem even before the birth of the child. He arranges that this specific soul should be placed into this particular body and born into this particular family so that all of the above-mentioned aspects of the person's life should occur with precision to that individual. The one factor which surely remains the domain of the child is whether he will choose to be good or bad, righteous or wicked. (See Rambam Hilchos Teshuva Chapter 5.)
Rabbi Soloveitchik zt"l often referred to these two aspects of the human soul-body entity - the predetermined and the non-predetermined - as Fate and Destiny. It is the challenge of each individual to take his Fate and transform it into his Destiny or to marshal all of one's inborn and acquired talents as well as the challenges and obstacles of one's initial environment and serve His Maker from within that framework to fulfill his Destiny. To complain about one's Fate is futile. It is precisely this environment that is best suited for that particular soul to live out its life, and it behooves the individual to utilize precisely this framework to excel and maximalize one's potential. Even if "no'ach lo l'adam shelo nivra mishenivra" (Eiruvin 13b) - the soul would not have chosen this existence and would rather remain in the heavenly bliss above without having to undergo the challenge of existence, "'achshav shenivra - y'fashpeish b'ma'asav!" - now that he has been placed in this world, let him search out his deeds and perfect his service of his Creator! (Compare Chazal's statement (Mo'eid Katan 28a) "children, life, and sustenance are not (solely - see Tosfos ibid.) dependent on merit but on mazal" and see R. Aryeh Kaplan's zt"l Handbook of Jewish Thought (Vol 2. Divine Providence 19:25-26)).
Every morning we recite three b'rachos of identity noting who we are, or, in other words, who G-d made us into by placing our souls into a particular body thus deciding for us our religion, social status, and gender. We then praise Him as the One "she'asa li kol tzarki" - Who made everything I need to actualize my potential. We then proceed to exalt G-d as the "Meichin mitz'adei gever" - Who prepares the footsteps of Man. This can be taken to refer not only to Hashem's giving us the ability to walk but also to His constant arranging of events in our lives by placing us at the appropriate, precise crossroads for our decision-making process (b'chira chafshis) to play itself out. All of these aspects are included in our Fate. We conclude the Birchos HaShachar by beseeching G-d to make our Fate as easy as possible: lo lidei nisayon v'lo lidei vizayon v'harchikeinu mei'adam ra... - "[may You] not lead us to trials or to embarrassment and distance us from evil people." Each morning as we prepare for another day, we note that it is G-d who placed us in our past environment and will continue to present us with appropriate challenges specifically tailored for us alone (our Fate), and we ask for His assistance and kindness in helping us succeed (our Destiny).
These concepts are all included in the Torah's adjuration against coveting another's possessions. The Torah guides us: "You were given exactly what you need to succeed in your mission in life. Do not get sidetracked by looking over your shoulder to another's material possessions and relationships. They are his Fate, not yours! Your Destinies are not the same so your tools for fulfilling them will not be the same! Be happy with what you have because that is what you need and were given through Hashem's specific Providence to enable you to live out your potential." As Rav Yissachar Frand shlita once noted, the Aseres HaDib'rot begin with theoretical belief in Hashem ('Anochi Hashem Elokecha) and end with emuna in practice. Thus, the prohibition of Lo Tachmod includes within it one of the fundamental principles of the Torah - that Hashem guides each individual specifically and uniquely on the road to his Destiny and provides him with all the tools necessary to achieve it. May our recommitment to the truths contained within all of the Ten Commandments allow us to have the confidence to utilize our unique package of Divinely ordained and delivered blessings, talents and challenges to actualize our unique potential in the service of our Creator.