Hebrews 4:14-16 (ESV)- Since then we have a great high priest who has passed through the heavens, Jesus, the Son of God, let us hold fast our confession.  For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin.  Let us then with confidence draw near to the throne of grace, that we may receive mercy and find grace to help in time of need.
The work of the high priest on the Day of Atonement was to enter into the holy of holies with blood from the sacrifice and sprinkle it on the mercy seat to make atonement for the sins of the people (Leviticus 16). Only the high priest could ever enter the holy of holies and then only once a year.
Jesus Christ is our high priest. He made the sacrifice of Himself and entered into the holy of holies and presented the offering to God. God accepted it and now there is forgiveness. The high priest entered every year. Jesus has entered once and for all and there is now no need of sacrifice for sin. His one sacrifice did for eternity what thousands of Day of Atonement sacrifices were not able to do: atone for sin perfectly, finally and victoriously.
There is no place for priests in the sense of offering sacrifice for sin, in the New Testament church. Jesus is the priest. This text is careful to point out that Jesus is not just another high priest. He is the great high priest. The word “great” is never used of any priest in the Old Testament economy. Jesus alone is the GREAT high priest. It tells us that he is better than any other priest. He is not just a high priest. He is a great one. He is superior to all other priests including the high priests and even Aaron himself.
The point being made here is that our access to God is only as good as the One who enables it to happen. Since we have a great high priest we can come into God’s presence with confidence. How Christians need to realize this more and more! Our access to God is not a matter of the strength of our faith or the perfections of our efforts to obey God.
Our ability to enter into the presence of God is based upon the excellencies of the One who is our priest. How excellent is Christ? Believers can stop having confidence to enter into the presence of God when Jesus ceases to be excellent and that will never happen. If you are His then you can go to God with confidence. What gives anyone the right to come into the presence of God with prayers that he can expect to be heard? Jesus Christ can and does. You can go to God without fear of rejection if Jesus is truly your great high priest. What a glory this is! I can approach God with confidence until Jesus ceases to be the great high priest who has offered up Himself on my behalf. When will that be? It will never be. I can enter into the presence of God with confidence for all eternity.