The sanctuary (temple or tabernacle) as it had stood on earth in the Old Testament dispensation had something “closed” about it. Though it testified to the relationship God had established between himself and his covenant people, the tabernacle also spoke of distance, of separation between God and his people. The veil in front of the Most Holy Place (behind which God dwelled) highlighted that separation, as did the walls of the tabernacle proper and the fence around the tabernacle courtyard. The same is true for the temple Solomon built. As the sanctuary John sees is “opened,” these barriers disappear. We could understand that to mean that people now have access to God, which of course is true (Romans 5:2; Hebrews 10:19–22). But “opened” means that traffic can flow in both directions. The next verse speaks not of saints entering but of angels exiting.
5 After this I looked, and the sanctuary of the tent of witness in heaven was opened,