If you were raised Catholic, you probably have a "view" of the priesthood a little different from someone raised in a non-denominational background. For example, the Catholic church has a set of rituals the priest must perform on a regular basis - everything from blessing ordinary water to turn it into holy water to saying the mass each day. In the Old Testament (OT), there was this idea of the religious leaders being called "priests" - not exactly in the sense of what the Catholic church may require, but similar. The most important thing about the OT priest was that he was "set aside" from the rest of the community in which he dwelt for the specific purpose of all the duties associated with worship and sacrifice. Their duties included such things as preparing the offerings each day which were to be burnt on the altar, intervening for the people of Israel before God in prayer, and the like. There was also this office of "High Priest". Basically, he was over all the other priests and saw to it they all knew their duties, but he had some duties of his own that the other priests could not perform. For example, he had the role of wearing the "Urim and Thummim" - something ancient Israelites used to cast lots to determine God's perspective on a matter. He also had the important duty of being the one to offer the sin offering for the people - on the Day of Atonement. It is this role as High Priest that "foreshadowed" the work of Christ on our behalf as our one true High Priest.
So now we have a high priest who perfectly fits our needs: completely holy, uncompromised by sin, with authority extending as high as God’s presence in heaven itself. Unlike the other high priests, he doesn’t have to offer sacrifices for his own sins every day before he can get around to us and our sins. He’s done it, once and for all: offered up himself as the sacrifice. The law appoints as high priests men who are never able to get the job done right. But this intervening command of God, which came later, appoints the Son, who is absolutely, eternally perfect. (Hebrews 7:26-28 MSG)
As High Priest, Jesus perfectly fulfilled all the duties and requirements of the High Priest, but as our perfect sacrificial lamb, without spot or blemish, he also performed the role of the perfect sacrifice. Once and for all, the sacrifice was offered - leaving no need for further sacrifice. His role in dying for mankind's sin made all the OT required sacrifices null and void - no longer necessary. In fact, his role as High Priest also did away with the need for the priest as the one to be the "intercessor" between God and man. Two "systems" of known religious occurrences were done away with in his life, death, burial and resurrection - the role of the priesthood on earth as a kind of "mediator", and the need for sacrificial offerings to continue.
As the perfect offering, his blood was shed - in so doing, his blood made full and complete atonement for our sins (covered over, never to be remembered again, removed as far as the east is from the west). As the High Priest, he is the only one now who stands making intercession for us before the heavenly Father, having opened the door of full access to God by those who will believe in him as their Savior. No longer needing a mediator - we enter into God's presence with boldness and confidence. Even the High Priest of the OT times did have a boldness or confidence, for if there was any impurity in his life, he could be struck dead in the presence of God in the Holy of Holies.
No other confidence is as great as that which we know because of our position IN Christ Jesus. No other position gives us such boldness. In ourselves, we could never get the "job done right" as it applied to making a permanent sacrifice for our sins - that is why the OT Law of Moses included the provision for the yearly sin offering during the feast known as the Day of Atonement. It was offered over and over again each year - because the sacrifice of the young bull could never accomplish the forgiveness of our sin. It was a "type" of what Christ would accomplish as he was lifted up on that cross so many years ago. It "foreshadowed" his shedding of blood on our behalf. The perfect given for the imperfect.
Two things our High Priest does for us - makes a way for us to enter into God's holy presence, and ends all need for "works" on our part as a means of making us righteous. Instead, we enter into the finished work he provides and in so doing, we stand righteous before God. Here is the challenge for many of us - we don't fully comprehend the magnitude of Christ's finished work on our behalf, nor do we trust it as enough to give us such boldness and free access to the Holy God. It is tough to give up on a "system" which seemed to be so ingrained for so many years, so maybe that is one of the reasons Israel had a tough time embracing Jesus as Messiah when he came. They became very anchored to the way things had been done for all those years and forgot that the "type" could be set aside once the "real deal" was in their midst.
I think God wants us to remember that we "set aside" anything we might have counted on in the way of religious performance in our past and to enter into fully the place of right-living God provides in his Son Jesus. In so doing, we are free to enter into what he has prepared for us - including free access to his presence, with boldness and confidence, and the ability to stop "trying" to be righteous. Instead, he declares and makes us "fully righteous" in Christ Jesus - what we do now is walk in the position we are placed into. If we want to continue in the old way of "trying" to live righteous when we are given freely "full righteousness", we probably don't fully understand the completed work of our High Priest. Just sayin!