Leviticus 22:4-9

The priesthood received a portion of some of the offerings, some of the devoted things that Israel brought to be offered to God; but they were only allowed to eat it if they themselves were clean.

I think that for our purposes, it is important for us to understand that the defiling thing (that which makes a person unclean) may not, of itself, be sin—or that the person has necessarily sinned by coming into contact with it. It is what they represent, or symbolize, that is important to us here. We are dealing here with a ritual. The defiling thing represents, it symbolizes, it typifies sin and its effects. This is not to say, though, that coming into contact with some of these things might not be potentially physically harmful—because disease may very well be communicated by coming into contact with a corpse, for example. Nonetheless, the possibility of defilement by sin is taught in every case in which God declares a person unclean and therefore unsuited to serve Him until the defilement is taken away through the washing ceremonies prescribed by Him.

Leviticus 22:6-7

God is even showing here that that person eats in the dark. They are away from the light of God's throne. They are no longer in communication with Him until communication is restored, until communion is restored when the person has gotten rid of his uncleanness, gotten rid of that sin. This has awesome ramifications to it. And it is an awfully good thing that God looks on the heart. It is an awfully good thing He is merciful and full of grace and that we are surrounded by the sin offering (we are going to get into next) or we would never be acceptable before God. Because we have so many creeping things and we have so much leprosy, we would never be acceptable in His sight so that we could eat from His table.