The old Test example of the tabernacle. The sacrifice was upon the alter. The Laver was between the alter and the holy place. To enter the holy place, you had to wash, else the penalty was death. They didn't wash after they were already in the holy place.
Heb 10:19-22, "Therefore, brothers, since we have confidence to enter the Most Holy Place by the blood of Jesus, by a new and living way opened for us through the curtain, that is, his body, and since we have a great priest over the house of God, let us draw near to God with a sincere heart in full assurance of faith, having our hearts sprinkled to cleanse us from a guilty conscience and having our bodies washed with pure water."
Again, you have the blood and water. Only after having the blood and water could you enter the holy place.
Heb 9:19-22 "When Moses had proclaimed every commandment of the law to all the people, he took the blood of calves, together with water, scarlet wool and branches of hyssop, and sprinkled the scroll and all the people. 20He said, "This is the blood of the covenant, which God has commanded you to keep." In the same way, he sprinkled with the blood both the tabernacle and everything used in its ceremonies. In fact, the law requires that nearly everything be cleansed with blood, and without the shedding of blood there is no forgiveness."
Again, we have the water and the blood being used together. The power is in the blood, because without the sheding of blood, there is no forgiveness.