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…" (Hebrews 10:19-21)
The sin of Adam and Eve broke their unique relationship with God. God then "placed on the east side of the Garden of Eden cherubim and a flaming sword flashing back and forth to guard the way to the tree of life." (Genesis 3:24) That image of separation was portrayed in the curtain that hung in the temple. The Israelites were told to "make a curtain of blue, purple and scarlet yarn and finely twisted linen, with cherubim worked into it …The curtain will separate the Holy Place from the Most Holy Place." (Exodus 26:31-33)
The Most Holy Place was the place where the presence of God resided and the curtain, with cherubim woven into it, separated the people from the presence of God. But when Jesus died, "At that moment the curtain of the temple was torn in two from top to bottom." (Matthew 27:51) The perfect sacrifice offered by Jesus, our High Priest, opened the way for us to come into the very presence of God.
The privilege of having access to God is not based on our personal goodness, our spiritual maturity or anything we can do. We now come before God "by the blood of Christ, by a new and living way opened for us…" The sacrifice of Jesus is, as it were, the key that has opened the way into God's holy presence. And we have confidence to come to him because our audience with God is based entirely, totally, completely upon what Jesus has accomplished for us.
No matter how we feel, whether we are spiritually strong and vibrant, or struggling in our spiritual life, we can come into the presence of God "with confidence" - not personal confidence, but confidence that Jesus has made it possible for us.