Priests performed very important tasks under the Old Covenant, with their primary purpose being a representative of man to God. The mediation that the priest offered was mainly through offering sacrifices and intercession to God. Priests, including the high priest, could only come from the tribe of Levi, and were separate from the people.

Under the New Covenant, things are very different, however. The high priest, under whom all other priests must serve is Jesus Christ, who did not bring an animal sacrifice to God, but instead offered Himself as the sacrifice. Peter recognized that the priestly functions in the church would not be performed by a special group of men, but instead they would be performed by all Christians. By virtue of this, all Christians are priests in God’s sight. Peter said, speaking of all Christians, “Ye also, as lively stones, are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ” (1 Peter 2:5).  

Paul exhorted the Roman Christians, “I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service” (Romans 12:1). Only priests were allowed to offer sacrifices under the Old Covenant, so since Paul begged Christians to offer themselves as living sacrifices, he agrees with Peter that Christians are “an holy priesthood.”

Since all Christians are priests, that means that no Christian has to rely on a mere man as mediator between him and God. A Christian needs only go through the great high priest, Jesus Christ.  “For there is one God, and one mediator between God and men, the man Christ Jesus” (1 Timothy 2:5).  

Under the old covenant, men from the tribe of Levi were appointed to their priestly duties in elaborate rituals. They were clothed in ceremonial garments, and ritually cleansed of their sins. Of prime importance in their appointment was ceremonial washing in water, and sprinkling of the sacrificial blood on them. Christians today put on the ceremonial priestly garments, wash in water, and are sprinkled with the blood of Christ’s sacrifice when they obey the Lord in baptism. Paul wrote, “For as many of you as have been baptized into Christ have put on Christ” (Galatians 3:27). As the Christian obeys Christ in baptism, he qualifies to come before the Heavenly Father, because he is symbolically clothed in the priestly garments. As the Christian is immersed in water, the penitent believer makes contact with the cleansing blood of the Lamb of God, Jesus Christ. Paul reminded the Romans what they had done: “Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death?” (Romans 6:3). As the believer is baptized into the death of Christ, she contacts the cleansing blood of Christ. “Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water” (Hebrews 10:22).