They must be holy to their God and not profane the name of their God. Because they present to the LORD the offerings made by fire, the food of their God, they must be holy.
Jewish Publication Society of America Version (JPS1917) - Leviticus 21:6 >They shall be holy unto their God, and not profane the name of their God; for the offerings of the LORD made by fire, the bread of their God, they do offer; therefore they shall be holy.