This applies to something I posted elsewhere. The old covenant priests were commanded to cleanse themselves while they worked so that they didn't die. Handling sacrifices for sin and walking on the earth defiled them even though they were holy. For this reason, they were commanded to cleanse themselves with water in the brass basin by the altar.
Thou shalt also make a laver [of] brass, and his foot [also of] brass, to wash [withal]: and thou shalt put it between the tabernacle of the congregation and the altar, and thou shalt put water therein. For Aaron and his sons shall wash their hands and their feet thereat: When they go into the tabernacle of the congregation, they shall wash with water, that they die not; or when they come near to the altar to minister, to burn offering made by fire unto the LORD: So they shall wash their hands and their feet, that they die not: and it shall be a statute for ever to them, [even] to him and to his seed throughout their generations. Exodus 30:18-21
Likewise, in our service to GOD, we become defiled by the world or sin, and must continually be cleansed by the spirit, lest we die.
How this relates to your post is that approaching GOD in an unclean condition is just doing dead works.