Charles Ellicott Commentary Leviticus 21:17

"Speak unto Aaron, saying, Whosoever he be of thy seed throughout their generations that hath a blemish, let him not approach to offer the bread of his God." — Leviticus 21:17 (ASV)

Whoever he is of thy seed. —Better, any man of thy seed throughout their generations; that is, any of the descendants throughout all future times, who have not been disqualified for service in the sanctuary by their parents contracting illegal alliances, are still subject to the following regulations.

To offer the bread of his God. —That is, shall not officiate at the sacrifices. (See Leviticus 21:6 and Leviticus 3:2.)