John had seen Jesus’ vision (Revelation 1:12) and had heard words to write down for the seven churches (Revelation 1:10; Revelation 2:1 – 3:22). But now he again sees. The word “behold” tells the reader that John’s attention was captured by what he saw. John was on the little island of Patmos in the Aegean Sea, surrounded by whatever rocks or sand or trees there may have been around him in his island prison. But suddenly his attention was diverted from the rocks or sand or trees to a door. The reader (including the members of the seven churches) is meant to follow John’s gaze as he beholds this heavenly door.
1 After this I looked, and behold, a door standing open in heaven! And the first voice, which I had heard speaking to me like a trumpet, said, “Come up here, and I will show you what must take place after this.”