Verse 1: “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.’”
The gate of Heaven had been closed before. But this gate was flung open when Jesus delivered sinners from their iniquities by coming to this earth, being baptized by John, dying on the Cross, and rising from the dead again. Through his angels, God revealed to the Apostle John what awaits the world in the end times.