Why can't we approach God without Christ?

The necessity of going through Christ to approach God arises from the holiness of God and the sinfulness of man. Hebrews 9 emphasizes that without the shedding of blood, there is no remission of sins. Our own works and efforts are insufficient for approaching the holiness of God. The high priest of the Old Testament had to offer sacrifices first for himself and then for the people, illustrating that access to God is contingent upon valid atonement. Only through the blood of Christ, our perfect High Priest, can we be given access to God without fear of condemnation. His sacrifice was sufficient to cover all our sins, making it possible for us to stand justified before the Father.