There are a lot of rules here for the priests, and essentially it came down to two things. As priests serving before God, they were to be clean and without defect.
As such, the regular priests were not to touch any dead bodies unless it was the body of a close relative. And for the high priest, he was not allowed to touch a dead body at all. To do so would make them unclean.
They also couldn’t marry a woman who had been a prostitute, or a divorced woman, or in the case of the high priest, even a widowed woman.
And priests could not have any physical defects if they were to serve before God. They couldn’t be blind, lame, or have an other such physical problems.
Why? I think it was because of who the priests were representing, particularly the high priest. The high priest in particular was a symbol of Jesus Christ. And Christ was perfect and untouched by sin.
Death was the result of sin, and so the priests were not to be touched by it, even to the point of marrying a widow, in the case of the high priest.
Marrying a prostitute was definitely out for obvious reasons. And marrying a divorced woman was also out, probably because God considered it adultery (as Jesus pointed out in Matthew 5 and 19).
And having a physical defect would mar the image of the perfect High Priest, although it was no fault of the Aaronic priest himself.
But there is one big difference between Christ, our High Priest, and the priests of that day.
When the priests of that day touched something unclean, whether it was a dead body, leprous skin, or whatever it may have been, the priest himself became unclean, and needed to be cleansed.
But Jesus touched the leper, he touched dead bodies, he touched the lives of the prostitute and the sinner, but instead of becoming unclean himself, he made them clean. He made them whole. He made them holy.
And God does the same with us. He takes us in our sin, in our imperfections, he touches us, and makes us clean, whole, and holy. As God told the people, “I the LORD am holy—I who make you holy.”
Six times he repeats those words in these two chapters. We don’t make ourselves holy. It is God who makes us holy through the blood of Jesus.
As it says in Ephesians,
…Christ loved the church and gave himself up for her to make her holy, cleansing her by the washing with water through the word, and to present her to himself as a radiant church, without stain or wrinkle or any other blemish, but holy and blameless. (Ephesians 5:25-27)
