What happened symbolically in the services of the earthly sanctuary happens in reality in the heavenly sanctuary. After His ascension our Savior began His work as our High Priest: “Christ has not entered the holy places made with hands, which are copies of the true, but into heaven itself, now to appear in the presence of God for us” (Hebrews 9:24). LF 173.6
The service of the priest in the first apartment, “behind the veil” which separated the Holy Place from the outer court, represents the work that Christ began when He ascended. In the daily service the priest presented before God the blood of the sin offering and also the incense that went up with the prayers of Israel. Likewise, Christ pleaded His blood before the Father for sinners and presented to Him the prayers of repentant believers with the fragrance of His own righteousness. This was the ministry in the first apartment of the sanctuary in heaven. LF 173.7
The faith of Christ's disciples followed Him to that first apartment when He ascended. This is where their hopes centered. “This hope we have as an anchor of the soul, both sure and steadfast, and which enters the Presence behind the veil; where the forerunner has entered for us, even Jesus, having become High Priest forever.” “He entered once for all into the Holy Place ... with His own blood, thus obtaining eternal redemption.” (Hebrews 6:19, 20; Hebrews 9:12, NRSV.) LF 174.1
For eighteen centuries this work continued in the first apartment of the sanctuary. The blood of Christ obtained pardon and acceptance with the Father for repentant believers, but their sins still remained on the books of record. As in the symbolic service there was a work of atonement at the close of the year, so before Christ's work for humanity is done there is a work of atonement to remove sin from the sanctuary. This began when the 2,300 days ended. At that time our High Priest entered the Most Holy Place to cleanse the sanctuary. LF 174.2