“...and be unclean until the evening.”
I have worked with children in summer camps for many years, and I have seen my share of unclean boys (and girls). Sometimes the mothers would get hysterical to see so much dirt on their children. There was dirt on their knees, hands, faces, hair and in some noses as well.
That was the natural consequence of taking a group of energetic kids to the park. You see, a child doesn’t just play; he interacts with dirt until he becomes “one with the earth.” They become unclean as they have fun in the mud, but do not worry; a good bath will take care of the dirt, that is, if you can make the child take a “good” bath.
There is another kind of uncleanness which is invisible, and hard to clean at the same time. I’m referring specifically to the unclean heart. Satan was created as an angel of light and marvelous in all his ways until his heart became unclean.
Pride entered into his heart and with it, the impossible desire to become God; but there was only one small problem, there was already a God! Since then, Satan became unclean and an enemy of the Lord. What began in his heart, now developed into a full blown rebellion against Yahweh in which he persuaded a myriad of angels to join him in his doomed “empire.” Those angels became known as demons or unclean spirits.
Uncleanness was later transmitted to humanity through the "valiant" efforts of Adam and Eve. Though we still retain God’s image it has been perverted and distorted by sin. Thank God we were unclean only until the evening; for it was at that time that Jesus shed his blood to clean our sins forever!