What does Hebrews 9:8 mean?

Prior verses explained how the old covenant included two rooms, one inside the other, within the temple. The first curtain designated a line which only the priests could cross. Inside that same room was another curtain, walling off an area where only the high priest could go, and only once per year, and only when bearing the proper sacrifice.

As explained here, this was meant to symbolize an inherent weakness of the old covenant. The writer of Hebrews has been careful to point out that the old covenant is not "wrong," it is merely "imperfect" (Hebrews 7:11; 8:7). More to the point, this letter has gone to great lengths to show how this new covenant, through Jesus Christ, has always been God's ultimate plan. The two-room arrangement described in this passage is part of the symbolism God intended with the old covenant. In that arrangement, man is separated from God, and the rituals of the priesthood can only temporarily satisfy the requirements of God's justice.

This symbolism is key to a unique event during the crucifixion of Jesus Christ. According to Matthew 27:50–51, when Jesus' sacrifice on the cross was complete, the curtain separating God and men was torn—from top to bottom. At that point, both symbolically and literally, there was no longer a barrier separating the Creator from His creation.

However, just because the barrier has been removed by God does not mean man is incapable of creating one of his own, acting as if that barrier still exists. As the writer of Hebrews points out, those who still try to seek God under the old covenant are denying themselves the benefit of the new covenant, which includes access to "the holy places."