The beginning of Parshat Emor states several laws pertaining to Kohanim and other laws pertaining to all Jews. Kohanim may not shave their beards with a blade, be in close proximity with the deceased, or marry divorcees. Furthermore, a Kohen who has a birth defect, is lame, or is a lefty can not perform the Avoda. Why do the Kohanim have so many more rules and restrictions than the rest of the nation?
When Hashem promised Aharon that his children would perform the Avoda, He did not say that nearly half of the Kohanim would not be allowed to serve. Doesn't the Torah, a book of ethics, teach us to love every Jew, regardless of ability? How can Hashem be so selective?
A possible answer may be found in Parshat Shemini, when Nadav and Avihu brought an À_ ___ on the Mizbeach. Rashi quotes Rabbi Yishmael as saying that Nadav and Avihu were drunk. This was not proper behavior for Kohanim; consequently, they were punished. Hashem did this to show that Kohanim were expected to set an example for the rest of Bnai Yisrael. To prevent any more transgressions, Hashem set strict guidelines to insure that Bnai Yisrael could always look up to the Kohanim.
This may explain the strict rules given to the Kohanim, but why must a Kohen be physically perfect? Isn't his Emunah (faith) and devotion to Hashem what really matters? Furthermore, the Torah gives a long list of specific blemishes, and concludes by saying _À ___...___ __, "He that has a blemish shall not approach the Heichal," a statement that includes all defects not specifically mentioned. For some blemishes, such as Tzaraat and blindness, it is obvious why a Kohen would not be able to serve. The Kohen might cause a Korban to be Tameh if he has Tzaraat, and if he can not see, he may hurt himself. However, the Torah also lists superficial defects, such as eyebrows that look like one big brow, or a sunken nose. In addition, a Kohen whose arm or leg has been broken may not serve in the Bait Hamikdash, even after the limb healed. Why does the Torah discriminate against these Kohanim?
The whole idea of bringing sacrifices to Hashem seems difficult to grasp. What benefit can Hashem possibly get from burnt animals? The Korban is a physical way for Bnai Yisrael to show their love for Hashem. By bringing the best of their produce and cattle, Bnai Yisrael show that they want to give Hashem the best of what they own. The same principle may be applied to the Kohanim. Hashem does not discriminate against superficial defects; rather, by only allowing the healthiest Kohanim to serve in the Bait Hamikdash, Bnai Yisrael demonstrate their great love for Hashem.