Right after you were born, the blood and vernix on your body was washed off by a nurse or even your mom or dad. Have you taken a bath or shower since the day you were born? Of course you have. Our bodies continually become dirtied, requiring new cleansing. It is the same way with us spiritually. Even after we are born again by the Spirit of God (John 3:1–8), we continue to sin. We have to be washed for the first time by Jesus, but He also continues to wash us of our sins.
The Lord said to Moses, “You shall also make a basin of bronze, with its stand of bronze, for washing. You shall put it between the tent of meeting and the altar, and you shall put water in it, with which Aaron and his sons shall wash their hands and their feet. When they go into the tent of meeting, or when they come near the altar to minister, to burn a food offering to the Lord, they shall wash with water, so that they may not die. They shall wash their hands and their feet, so that they may not die. It shall be a statute forever to them, even to him and to his offspring throughout their generations.” (Exodus 30:17-21)