‘After these things I looked, and behold, a door standing open in heaven. And the first voice which I heard was like a trumpet speaking with me, saying, “Come up here, and I will show you things which must take place after this.”’ (Revelation 4:1 NKJV).

The book of Revelation can be understood as having three divisions. Jesus instructed the apostle John to “write the things which you have seen, and the things which are, and the things which will take place after this” (Rev. 1:19). Revelation 4:1 begins the “things which must take place after” section, which is the third and future section. Beginning in chapter four, John writes from a heavenly perspective having been called up to heaven by the “first voice,” which belonged to Jesus, whose voice sounded “like a trumpet” (see Rev. 1:10-11).
 
Jesus drew back the curtain, unveiling the last days to John from heaven’s viewpoint. He did this to encourage believers to be faithful, watchful and confident that the Lord is sovereign and coming again.