"For Christ did not enter a man-made sanctuary that was only a copy of the true one: he entered heaven itself, now to appear for us in God's presence." (Hebrews 9:24)
An understanding of the structure of the temple in Jerusalem and the work of the high priest in the Mosaic Law is an important starting place in understanding the above passage from the book of Hebrews. The temple was divided by a curtain which separated the Holy of Holies, where the presence of God resided, from the Holy Place where the priests offered daily sacrifices to God. Once a year, on the Day of Atonement, the high priest would take the blood of an animal and enter into the Holy of Holies on behalf of the sins of the people. This sacred ritual was performed for centuries and pointed to the future, when God in Jesus Christ would offer himself as the atoning sacrifice for all time.
Our High Priest in Heaven
When Jesus offered himself on the cross, he became both the atoning sacrifice and the High Priest entering the presence of Almighty God "for us". When the Father accepted Jesus he also accepted all those whom Jesus represents. Therefore our acceptance by God is absolutely certain, for it is not based on anything we do, but upon everything that Jesus has done for us. Peter in his epistle sheds more light on the subject by telling us that Jesus died for our sins "in order to bring you to God." (1 Peter 3:18)
We can now face death, not with fear and uncertainty, but with joyful expectation, knowing that the moment we close our eyes in death we will be accepted into the presence of the Father because Jesus, our perfect sacrifice, represents us in heaven.