כָּל־אִ֞ישׁ אֲשֶׁר־בּ֣וֹ מ֗וּם מִזֶּ֙רַע֙ אַהֲרֹ֣ן הַכֹּהֵ֔ן לֹ֣א יִגַּ֔שׁ לְהַקְרִ֖יב אֶת־אִשֵּׁ֣י יְהוָ֑ה מ֣וּם בּ֔וֹ אֵ֚ת לֶ֣חֶם אֱלֹהָ֔יו לֹ֥א יִגַּ֖שׁ לְהַקְרִֽיב׃
no man of the seed of Aaron the priest, that hath a blemish, shall come nigh to offer the offerings of the LORD made by fire; he hath a blemish; he shall not come nigh to offer the bread of his God.
Read kabbalistic (mystical) interpretation of Leviticus 21:21: and classical mystical sources.