Speak unto Aaron and to his sons, that they {a} separate themselves from the holy things of the children of Israel, and that they profane not my holy name in those things which they hallow unto me: I am the LORD.

(a) Meaning, that the priests abstain from eating, as long as they are polluted.

Wesley's Notes

22:2 Separate themselves - When any uncleanness is upon them, as appears from Lev 22:3,4. From the holy things - From eating of those parts of the offerings, which belong to them. Only of the tithes they might eat. They - The children of Israel. And it ill became the priests to profane or pollute what the people did hallow.

Jamieson-Fausset-Brown Bible Commentary

2. Speak unto Aaron and to his sons, that they separate themselves from the holy things-"To separate" means, in the language of the Mosaic ritual, "to abstain"; and therefore the import of this injunction is that the priests should abstain from eating that part of the sacrifices which, though belonging to their order, was to be partaken of only by such of them as were free from legal impurities.

that they profane not my holy name in those things which they hallow unto me, &c.-that is, let them not, by their want of due reverence, give occasion to profane my holy name. A careless or irreverent use of things consecrated to God tends to dishonor the name and bring disrespect on the worship of God.

Matthew Henry's Concise Commentary

22:1-33 Laws concerning the priests and sacrifices. - In this chapter we have divers laws concerning the priests and sacrifices, all for preserving the honour of the sanctuary. Let us recollect with gratitude that our great High Priest cannot be hindered by any thing from the discharge of his office. Let us also remember, that the Lord requires us to reverence his name, his truths, his ordinances, and commandments. Let us beware of hypocrisy, and examine ourselves concerning our sinful defilements, seeking to be purified from them in the blood of Christ, and by his sanctifying Spirit. Whoever attempts to expiate his own sin, or draws near in the pride of self-righteousness, puts as great an affront on Christ, as he who comes to the Lord's table from the gratification of sinful lusts. Nor can the minister who loves the souls of the people, suffer them to continue in this dangerous delusion. He must call upon them, not only to repent of their sins, and forsake them; but to put their whole trust in the atonement of Christ, by faith in his name, for pardon and acceptance with God; thus only will the Lord make them holy, as his own people.