The following Dvar Torah from Rav Yochanan Zweig shlita, Rosh Yeshiva of the Talmudic University of Miami, presents a fresh perspective as to why we keep mitzvos. Hope you enjoy! Have a great Shabbos.
Command Aharon and his sons, saying... (6:2)
Rashi (ad loc) comments that the word "Tzav" (command) means enthusiastically encourage (the Kohanim) beginning now and for succeeding generations.
This would seem a little incongruous. After all, have you ever tried "commanding" someone and achieved that the person commanded feels "encouraged" or "enthusiastic"? Hardly. For a proper understanding of this concept try "commanding" your spouse to do the dishes and let us know how that works out for you.
In addition, how could Rashi say "to encourage the Kohanim for now and succeeding generations"? Commanding this generation of Kohanim to do their duty would seem difficult enough, how would this last for succeeding generations?
The word Mitzvah also etymologically has the root "Tzav" which is why Mitzvos are generally translated as commandments. This is, at best, an incomplete translation.
Both Targumim on this Possuk translate "Tzav" as "Paked" which means to appoint. This is also the exact same word that Moshe uses when he asks HaShem to appoint a leader in his stead over the Jewish people - "Yifkod HaShem..." (Numbers 27:16). This is a very important concept to understand. When HaShem first chose Moshe to go lead the Jewish people out of Egypt, a week long conversation ensued. This consisted, primarily, of Moshe arguing with HaShem. This would seem very odd, after all HaShem is telling him to go, how can Moshe possibly argue?
The answer is that HaShem was asking Moshe to accept a position of responsibility, and responsibility has to be accepted willingly. This is why when Moshe finally accepts to go with Aharon the Torah uses the same exact language of "Tzav" - "Vayetzavem Al Bnei Yisroel" (Shemos
6:13). The same is true by the entire Torah and Mitzvos which is also a derivative of "Tzav". They are a responsibility. That is why HaShem has to ask us to accept the Torah, and every soul has to be present at Mount Sinai and sign on for this obligation. The Torah and Mitzvos aren't merely rules we must keep. They are a complete agenda for the perfection of the world and we are signing on for the responsibility to see it fulfilled.
So too in our Parsha, HaShem is telling Moshe to appoint Aharon and his sons to the permanent role of Kohanim and to do it in an encouraging and enthusiastic manner in order that they should feel the same way. They aren't being commanded, they are being asked to accept a sacred responsibility. Once they accept it, this responsibility becomes binding for all succeeding generations.