Jesus was not only the sacrifice, but the high priest as well. Jesus offered Himself to take away the sin of the world.

"For such an high priest became us, who is holy, harmless, undefiled, separate from sinners, and made higher than the heavens; who needeth not daily, as those high priests, to offer up sacrifice, first for his own sins, and then for the people's: for this he did once, when he offered up himself." - Hebrews 7:26-27 KJV

"Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us." - Hebrews 9:12 KJV

After Jesus’ death, burial, and resurrection, it was necessary for Jesus, as the high priest, to offer His blood on the mercy seat in heaven to fulfill the tabernacle plan of salvation. Sin, from the beginning with Adam, had separated us. Jesus’ offering of His sinless blood in the heavenly Holy of Holies brought peace between Himself and man.

“Then the same day at evening, being the first day of the week, when the doors were shut where the disciples were assembled for fear of the Jews, came Jesus and stood in the midst, and saith unto them, Peace be unto you." - John 20:17-19 KJV

"And, having made peace through the blood of his cross, by him to reconcile all things unto himself; by him, I say, whether they be things in earth, or things in heaven." - Colossians 1:20 KJV

"To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation." - 2 Corinthians 5:19 KJV (John 20:21-23)

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost." - Acts 2:38 KJV