After these things I looked, and behold, a door standing open in heaven, and the first voice which I had heard, like the sound of a trumpet speaking with me, said, "Come up here, and I will show you what must take place after these things."Revelation 4:1(NASB)
Once John was charged to write the book of Revelation, when he met with the resurrected, glorified Lord Jesus in chapter 1, and having received Christ's 7 letters to the 7 churches in chapters 2-3, he is given a vision of the throne-room of God and commanded to, "Come up hither, and I will shew thee things which must be hereafter".
Not only was John given important information for the Churches, but he was also to 'see' and 'hear' what was going to happen beyond the current Church age - "after these things". After acting as God's heavenly, High Priest to Church-age saints and interceding as heaven's Mediator between God and man - John is shown how Christ will begin to take on His role of Judge, before returning to earth to claim His position as King of kings and Lord of lords.
"I looked, and, behold, a door was opened in heaven," John writes, "and the first voice which I heard was as it were of a trumpet talking with me." The angel who met John in the prologue was the same angel who accompanied him throughout the entire revelation of Jesus Christ - which the Father gave to His Son,... to give to John through His angel.
The apostle John was about to receive a preview of the future, which began with a vision of heaven in chapter 4, and moved to the worship of the Lamb of God in chapter 5. He saw the One Who seated on the throne had the appearance of crystal-clear jasper and a blood-red sardine stone, and John recorded that there was a rainbow surrounding the throne that reminded him of a brilliant green emerald.
Twice he was summoned to 'come up here". The same voice, which sounded like that of a trumpet in chapter 1, commanded him to join the heavenly host of angelic beings that surrounded the throne of God, by means of a door - which was standing open in heaven. And being 'in the spirit on the Lord's day', John was given an amazing insight into the future.. and greater revelation of Jesus Christ the Lamb of God and Lion of the tribe of Judah.
After Christ's revelation to the Churches ended, John's vison changed, and he was ushered into heaven - in spirit and in truth. He discovered that the heavenly scene into which he had been brought, was preparing to unseal a special scroll, which had been securely sealed by God Himself with seven seals.
As the heavenly scene unfolded John discovered that he was witness to the precursor of the prophesied judgement on earth - the day of the Lord.. which he recorded in chapters 6-19... when the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness.
The sight that John saw during chapters 4-5, were the heavenly preparation for that future time of great tribulation - recorded in chapters 6-19, which is to fall on a Christ-rejecting sinful world and which will bring Israel to national repentance, and punishment to the God-hating; Christ-rejecting; sinful world.
While John's body remained on earth, his spirit was translated into heaven, where he witnessed a vision of the angelic host that surround the throne of almighty God - the Ancient of Days. As he looked, John was introduced to four living creatures who worship God day and night and 24 elders, who were clothed in white raiment, with crowns of gold on their heads.
The vison of the throne-room of God; the worship of the Lamb Who was slain and the presentation of a seven-sealed scroll, which no-one but Lamb could break, are all part-and-parcel of the heavenly vision John saw in chapters 4 and 5.
It was after he had received Christ's revelation to the Church (chapters 1-3) but before the revelation of Christ to the world in His role as Judge (chapters 6ff), when the wrath of God which is poured out upon the children of disobedience, that the aged apostle John looked, "and behold, a door was standing open in heaven, and the first voice which I had heard, like the sound of a trumpet speaking with me, said to him, "Come up here, and I will show you what must take place after these things."
Let us remember that the one who reads, hears and takes to heart this amazing revelation is blessed - 'Blessed is he that reads, and those that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand".
Heavenly Father, thank You for the book of Revelation and for the greater insight and understanding it gives us into the Person and Work of the Lord Jesus; and of what is to take place after He comes to take the members of His mystic Body to be with Himself.. and how we should live in this present age. I pray that You would bless me as I read and take to heart all that is written in this final book of Scripture. Thank You that You are the eternal and immutable God Whose plans and purposes can never fail. Thank You that the cross of Christ and His glorious resurrection, which secured for us an eternal inheritance, by faith. I pray that all I say and do would give glory to You and that one day I may cast my crown before His feet for all Your goodness and grace to us and to all men - this I pray in Jesus' wonderful name, AMEN.