Charles Ellicott Commentary Leviticus 21:15

"And he shall not profane his seed among his people: for I am Jehovah who sanctifieth him." — Leviticus 21:15 (ASV)

Neither shall he profane his seed. —Better, And he shall not profane. That is, he is not to contract any of these forbidden marriages, so that he does not thereby degrade his offspring. This is because the children of such a union, as well as their mother, were excluded from the privileges of the priesthood, and were not permitted to partake of those portions of the sacrifices that constituted the special allowances for the officiating priests.