Albert Barnes Commentary Leviticus 21:4

"He shall not defile himself, [being] a chief man among his people, to profane himself." — Leviticus 21:4 (ASV)

The sense seems to be that, owing to his position in the nation, the priest is not to defile himself in any cases except those named in (Leviticus 21:2–3). The Septuagint appear to have followed a different reading of the text which would mean, “he shall not defile himself for a moment.” The explanation in the margin of our version is hardly in keeping with the prohibition to Ezekiel on a special occasion. See (Ezekiel 24:16).