Revelation 4:1

After this, I looked, and behold, a door open in heaven. After describing the works of the Church, what it was and what it would be like, he recapitulates from the birth of Christ, intending to say the same things differently. For he repeats the …

By the particle and, the several parts of this prophecy are usually connected: by the expression, after these things, they are distinguished from each other, chap. vii, 9; xix, 1. By that expression, and after these things, they are distinguished, and yet connected, chap. vii, 1; xv, 5; xviii, 1.

After this I looked,....

After this - Greek, “After these things”; that is, after what he had seen, and after what he had been directed to record in the preceding chapters. How long after these things this occurred, he does not say - whether on the same day, or at some subsequent time; and conjecture would be useless. The scene, however, is changed. Instead of seeing the Saviour standing before him Rev. 1, the scene is transferred to heaven, and he is permitted to look in upon the throne of God, and upon the worshippers there.

After this--Greek, "After these things," marking the opening of the next vision in the succession. Here is the transition from "the things which are" (Re 1:19), the existing state of the seven churches, as a type of the Church in general, in John's time, to "the things which shall be hereafter," namely, in relation to the time when John wrote.

How highly favored was the Apostle John! While his Master was on earth he was the favored disciple, permitted to lean his head upon His bosom as a token of the most familiar and loving communion. After our Lord had ascended, He had the same heart towards John and, finding him alone amidst the wild rocks of Patmos, He visited him on the Lord's-Day and revealed Himself to him in a most glorious manner.

How highly favored was the Apostle John! While his Master was on earth he was the favored disciple, permitted to lean his head upon His bosom as a token of the most familiar and loving communion. After our Lord had ascended, He had the same heart towards John and, finding him alone amidst the wild rocks of Patmos, He visited him on the Lord's-Day and revealed Himself to him in a most glorious manner. Brothers and Sisters, if Heaven should offer any one thing which we might choose—if ever the Lord should appear to us as He did to Solomon and say, "Ask what you will, and it shall be given you," be it ours to request that we may enjoy the closest possible fellowship with the Well-Beloved! If we might choose our portion among the sons of men, we could not select a happier, a holier, a more honorable lot than to abide in hallowed fellowship with Jesus, even as did the beloved disciple. Remember, John has not this privilege reserved unto himself. The innermost circle of fellowship is not for the seer of Patmos alone—there is room upon the bosom of Christ for other heads than his! The innermost heart of Jesus is large enough to hold more than one beloved! Despair not of gaining the choicest place! It is not easy to ascend into the hill of the Lord and to stand in His holy place, but if you are pure in heart. If you are fervent in spirit. If you are purged from earthly dross, and if you surrender yourself as a chaste virgin unto Christ, you may—even you may yet attain unto this rare and choice privilege of abiding in Christ and enjoying without ceasing His love shed abroad in your heart by the Holy Spirit. Leaving John, however, to whom the door in Heaven was so remarkably opened that his vision of the spiritual world excelled all others, we will content ourselves with gathering up the crumbs from his table while we muse upon one of the descriptions which fell from his pen.

A door was opened in heaven - This appears to have been a visible aperture in the sky over his head.