In the Rock and Roll era in which I grew up, there were many songs that referenced “Heaven’s Door.” According to Bob Dylan as well as Gun’s & Roses, “we’re knock, knock, knocking on heaven’s door.” Alicia Keys is going to “march up each step until she reaches heaven’s door.” The infamous Jimmy Hendricks (or was it Led Zeppelin?) made the phrase “stairway to heaven” common language in the 60’s. I’m sure there were, and still are, many other pop culture references to Heaven’s Door. But they have their origin in John’s vision. I would expect that the Apostle John understood the world in much the same way as others in his day. He sees the earth as being covered by a “firmament,” a large canopy that stretches over the earth. He may draw his views from Isaiah. The Prophet explains, “It is he (God) who sits above the circle of the earth, and its inhabitants are like grasshoppers; who stretches out the heavens like a curtain and spreads them like a tent to dwell in.” (Isaiah 40:22). This firmament keeps us from seeing beyond it into the heavenly realms. We have no idea what’s happening beyond it in the spiritual or heavenly realm. But in his vision recorded in the Book of Revelation, John sees a break in the firmament. He calls it a door. He writes in chapter 4, verse 1, “After this, I looked, and behold, a door standing open in heaven!” He sees what the normal physical eye cannot see.
Even though we’ve visited the moon and sent spacecraft into some rather distant reaches of outer space, the realities of heaven and the validity of John’s vision are in no way compromised. We still believe, at least I still believe, that heaven is a literal place but not necessarily a physical location that can be reached by a rocket ship or any kind of time travel from our physical, earthly position.
In his commentary on Revelation, M. S. Mills concludes his comments on this verse by writing, “What an inexpressible privilege it is to have Heaven’s door opened for us, to have the opportunity to view this ethereal scene! God has allowed us a preview of our eternal destiny, for in His love and through the gracious work of Christ, we need not fear the magnificent, awesome personage seated on that glorious throne. This fantastic privilege is solely based on the atoning work of Jesus Christ; otherwise, our sins would keep us eternally exiled from this: the Source of all holiness, the Source of all being, the Source of all life, and the Source of all power. The privilege we enjoy through Christ is the assurance that we will eternally be part of this scene and eternally have access to this supremely wonderful God! As believers, this is our happy, eternal lot.”