Revelation 4:1

After [seeing all] these things, I looked, and there in heaven I saw [a vision of] an open door, and the voice I had first heard speaking to me like [the sound of] a trumpet [See 1:10], said, "Come up here [i.e., to heaven], and I will show you the things which must happen after these things [i.e., the things just revealed]."

Revelation 1:10

I was in [i.e., under the influence of] the Holy Spirit on the Lord's day [i.e., Sunday], when I heard behind me a loud voice, like a trumpet,

Revelation 1:19

"So, write down the things that you have seen, and the things now going on, and the things that will happen later on.

Revelation 11:12

Then the two witnesses/prophets heard a loud voice from heaven saying to them, "Come up here." So, they went up to heaven in a cloud, and their enemies saw them.

Revelation 22:6

Then the angel [See 21:9] said to me, "These words are trustworthy and true. And the Lord, the God of the spirits of the prophets, sent His angel to show to His servants [i.e., through the apostle John] the things that must happen soon [See 1:1].

Matthew 3:16

After Jesus was immersed [by John], He came up out of the water and heaven was opened up before Him and He saw the Holy Spirit from God descending, as a dove, and landing upon Him.

Mark 1:10

And immediately upon emerging from the water, He saw the sky split open and the Holy Spirit descending on Him as a dove.

Luke 3:21

Now it happened when all the people had been immersed [by John], that Jesus was also immersed [by him]. And while Jesus was praying, heaven was opened

Acts 7:56

He said, "Look, I see heaven opened up and the Son of man standing at the right side of God."

Acts 10:11

and could see the sky open up and a huge sheet-like container being lowered to the ground by its four corners.

Revelation 16:17

Then the seventh [angel] poured out his bowl into the air, and a loud voice came out of the Temple from the throne [of God], saying, "It is over!" [i.e., the series of judgments have been completed].

John 16:13

However, when the Holy Spirit of truth comes, He will lead you [apostles] into all the truth. For He will not speak on His own authority, but will speak [only] what He hears [from the Father]. And He will tell you about the things that are to come.

Revelation 1:1-3

[This is the record of] the revelation of Jesus Christ, which God gave [Him] to show to His servants. [It contains] the things which were soon to happen, and Christ sent His angel [i.e., messenger] to inform His servant, [the apostle] John, [about them].

Treasury of Scripture Knowledge

Summary

After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will shew thee things which must be hereafter.

Bible References

A door

Matthew 3:16
After Jesus was immersed [by John], He came up out of the water and heaven was opened up before Him and He saw the Holy Spirit from God descending, as a dove, and landing upon Him.
Mark 1:10
And immediately upon emerging from the water, He saw the sky split open and the Holy Spirit descending on Him as a dove.
Luke 3:21
Now it happened when all the people had been immersed [by John], that Jesus was also immersed [by him]. And while Jesus was praying, heaven was opened
Acts 7:56
He said, "Look, I see heaven opened up and the Son of man standing at the right side of God."
Acts 10:11
and could see the sky open up and a huge sheet-like container being lowered to the ground by its four corners.

The first

Revelation 1:10
I was in [i.e., under the influence of] the Holy Spirit on the Lord's day [i.e., Sunday], when I heard behind me a loud voice, like a trumpet,
Revelation 16:17
Then the seventh [angel] poured out his bowl into the air, and a loud voice came out of the Temple from the throne [of God], saying, "It is over!" [i.e., the series of judgments have been completed].

And i

Revelation 1:19
"So, write down the things that you have seen, and the things now going on, and the things that will happen later on.
Revelation 22:6
Then the angel [See 21:9] said to me, "These words are trustworthy and true. And the Lord, the God of the spirits of the prophets, sent His angel to show to His servants [i.e., through the apostle John] the things that must happen soon [See 1:1].
John 16:13
However, when the Holy Spirit of truth comes, He will lead you [apostles] into all the truth. For He will not speak on His own authority, but will speak [only] what He hears [from the Father]. And He will tell you about the things that are to come.