Christ was crucified, buried, resurrected, and ascended to consummate salvation by atoning for sin and completing the requirements for the atonement in the heavenly “Holy of Holies” – securing forever salvation for all who would ever put their genuine faith in Him. This occurred in AD 30.
However, the full access into the heavenly Holy of Holies was not yet fully consummated until He came back out and returned at His second coming Parousia in AD 66. It was necessary for the symbolic earthly first tabernacle to be destroyed in order for His redeemed saints to be able to enter the heavenly “Holy of Holies” or “Holiest of All” into the presence of God.
“6Now when these things had been thus prepared, the priests always went into the first part of the tabernacle, performing the services. 7 But into the second part the high priest went alone once a year, not without blood, which he offered for himself and for the people’s sins committed in ignorance; 8the Holy Spirit indicating this, that THE WAY INTO THE HOLIEST OF ALL WAS NOT YET MADE MANIFEST WHILE THE FIRST TABERNACLE WAS STILL STANDING.” (Heb. 9:6-8).
The “first tabernacle” made of human hands was an exact copy of the heavenly true Tabernacle (Heb. 8:1), but the animal blood sacrifices were not able to provide humans access into the holy presence of God. The more perfect “heavenly tabernacle” access was to be fully consummated by Christ, which would forever open access to all redeemed saints.
“11But Christ came as High Priest of the good things to come, WITH THE GREATER AND MORE PERFECT TABERNACLE not made with hands’ that is, not of this creation.” (Heb. 9:11).
Jesus Christ, the Son of God, sprinkled His own blood on the heavenly tabernacle and the vessels of the ministry as required by the law for purification. For without shedding of blood there is no remission. So, on earth, the copies of things in heaven were practiced by the Jewish high priest according to the law.
Christ did not enter the holy places made with hands, which are copies of the true. But He entered into heaven itself to appear in the presence of God for us in the true Holy of Holies. He did not have to offer Himself often as the Jewish high priest under the law was required to do with the blood of animals. Instead He was offered once to bear the sins for all.
“27Then likewise he sprinkled with blood both the tabernacle and all the vessels of the ministry. 22And according to the law almost all things are purified with blood’ and without shedding of blood there is no remission. 23Therefore it was necessary that the copies of the things in the heavens should be purified with these, but the heavenly things themselves with BETTER SACRIFICES than these. 24For 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; 25not that He should offer Himself often, as the high priest enters the Most Holy Place every year with blood of another — 26He then would have had to suffer often since the foundation of the world; BUT NOW, ONCE AT THE END OF THE (Old Covenant) AGES, HE HAS APPEARED TO PUT AWAY SIN BY THE SACRIFICE OF HIMSELF.” (Heb. 9:21-26).
Christ has fully paid the atonement for sin once and for all. His atonement is an eternal one. It is effective for everyone and anyone who puts their genuine saving faith in Him (past and future). He came back out of the heavenly Holy of Holies and appeared a second time at His Parousia in AD 66-70. This time, His coming was apart from sin (the sin payment was done, but instead it was to consummate the New Heavens and Earth cosmological order under His blood, and to save/rescue those faithful believers in the 1st century who were under great persecution and EAGERLY WAITING for Him.
“28so Christ was offered once to bear the sins of many. To those who eagerly wait for Him (first century saints) He will APPEAR A SECOND TIME, apart from sin, FOR SALVATION (RESCUE).” (Heb. 9:28).
See also related “Topic Studies & Terms”:
“Parousia”
“Rapture”
Related full “Study Series” (available upon request if not hyperlinked):
[For a more in-depth study see eschatology “Study Series 14 Lesson 4 Resurrection: Expectations/Experiences”]
[For a more in-depth study see eschatology “Study Series 14 Lesson 7 The Parousia Acts 1:9-11”]