Honoring the Kohanim

VaYikra 21:8 You shall sanctify him, for he offers the food of your G-d; he shall remain holy to you, for holy am I Hashem, Who sanctifies you.

We are commanded to exalt the descendants of Aharon, to show honor and deference, and to assign to them a high degree of holiness and dignity, even overriding their own objections. All this is for the glory of Hashem (exalted be He), since He has taken them for His service and the offering of His sacrifices. The Sages interpret this verse thus: "You shall sanctify him in all matters appertaining to holiness: that is to say, he shall be first in all holy matters (e.g. the reading of the Torah); he shall have the first right to recite the Benediction at a meal; and he shall be first to receive a seemly portion." (Git. 59b)

The Sifra also says: "'You shall sanctify him - even against his will"; that is to say, this is a Mitzvah laid upon us, and it does not depend on the Kohen's wishes.

Moreh Nevuchim 3, 44

"In order to raise the estimation of the Temple, those how ministered therein received great honor; and the Kohanim and the Leviim were therefore distinguished from the rest'"