Rashi on Leviticus 21:24/רש"י על ויקרא כ״א:כ״ד

1וידבר משה AND MOSES TOLD this command,

2אל אהרן ואל בניו ואל כל בני ישראל UNTO AARON AND UNTO HIS SONS AND UNTO ALL THE CHILDREN OF ISRAEL — He told it to the Israelites although they were not directly concerned with these commands in order to admonish the court regarding the priests (i. e. that the authorities should watch over the sanctity of the Sanctuary and prevent priests with a bodily blemish from officiating) (Sifra, Emor, Chapter 3 12).