They shall not make any part of their head bald, nor shall they shave off the corner of their beard, nor make any gashes in their flesh... They shall be holy to their G-d (Lev. 21:5-6)
In ancient times it was the custom of idolatrous priests to alter their appearance, as a symbol of their status. Without these external markings their distinction would not be apparent, and everyone would know that they engaged in the same abominations as their fellow idol worshippers. By contrast (as if a comparison may be drawn!), kohanim (the descendants of Aaron) do not need any external signs of their exalted holiness. They are already holy, and are recognizable by their good deeds. (Maharil Diskin)
For any man in whom there is a blemish shall not approach (Lev. 21:18) When Rabbi Jacob was appointed chief rabbinical authority of the city of Lissa he had many opponents. One day he approached their leader and asked him why he objected. "Do you think I am not enough of a scholar? Are you dissatisfied with my qualifications?" "Oh, no," the man replied, "it's just that you are too young. It doesn't look nice to have a person your age as our head." "In that case," the Rabbi replied, "you needn't worry. I promise you that it is a 'temporary blemish,' and that with every passing day it will lessen..." (Mei'otzareinu Hayashan)
Therefore, shall you keep my commandments, and do them ("otam"); I am the L-rd (Lev. 22:31)
The letters of "otam" can be rearranged to form the word "emet," truth. From this we learn the importance of approaching mitzvot (commandments) truthfully, and not being deceived into thinking we have an unlimited amount of time to do them, as it states in Ethics of the Fathers: "Do not say, 'When I will have free time I will study.' " Rather, we should be aware that time is short, and "collect" as many mitzvot as possible in this world. (Mipi HaShemua)
You shall not defile ("techal'lelu") My holy Name; and I shall be sanctified among the Children of Israel (Lev. 22:32)
According to the Zohar, the root of the Hebrew word for defilement is "chalal," meaning an empty space. G-d's holy Name becomes defiled if we act as if the place we is standing on is devoid of Him. (Nefesh HaChaim)
Reprinted from the Acharei Mos-Kedoshim 5762/2002 edition of L’Chaim
