In the Old Testament, the annual Day of Atonement was the most solemn day on the calendar. Today it’s known as Yom Kippur. In the OT it was a day of purifying. And it was a day set apart for the high priest to enter inside the veil of the Holy Place with the blood a bull and then of a goat. It was a sacrifice in the presence of God to atone for the sins of the people and for the priest himself.
This act of bringing blood behind the curtain was very solemn act. A mis-step and the sacrifice would be rendered unaccepted and the priest could die (Leviticus 10:1–3). In many ways the acceptability of the sacrifice before God was evidenced by the re-emergence of the priest before the people. It’s not hard to imagine the anxiety and the eagerness of those outside the temple awaiting the priest’s return from behind the curtain.
The Day of Atonement is clearly in the mind of the writer of Hebrews in 9:1–10:14 and specifically in 9:27–28 where we read,
And just as it is appointed for man to die once, and after that comes judgment, so Christ, having been offered once to bear the sins of many, will appear a second time, not to deal with sin but to save those who are eagerly waiting for him.
Christ is our High Priest and his sacrifice on the cross for our sins has been made once-for-all. God has accepted the sacrifice as evidenced in the resurrection. But in a sense we are still waiting for our High Priest to emerge before our eyes.
As Christians we have been called to a heightened expectancy similar to that experienced on the Day of Atonement. Our High Priest will one day return before our eyes. And until he does we are called to eagerly await his appearance.