John 1:51
"And he saith unto him, Verily, verily, I say unto you, Hereafter ye shall see heaven open, and the angels of God ascending and descending upon the Son of man."
Cross References (ranked by relevance)
And he dreamed, and behold a ladder set up on the earth, and the top of it reached to heaven: and behold the angels of God ascending and descending on it.
And said, Behold, I see the heavens opened, and the Son of man standing on the right hand of God.
And straightway coming up out of the water, he saw the heavens opened, and the Spirit like a dove descending upon him:
And there appeared an angel unto him from heaven, strengthening him.
And Jesus said, I am: and ye shall see the Son of man sitting on the right hand of power, and coming in the clouds of heaven.
And saw heaven opened, and a certain vessel descending unto him, as it had been a great sheet knit at the four corners, and let down to the earth:
And suddenly there was with the angel a multitude of the heavenly host praising God, and saying,
And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him:
Now it came to pass in the thirtieth year, in the fourth month, in the fifth day of the month, as I was among the captives by the river of Chebar, that the heavens were opened, and I saw visions of God.
Now when all the people were baptized, it came to pass, that Jesus also being baptized, and praying, the heaven was opened,
Then the devil leaveth him, and, behold, angels came and ministered unto him.
And to you who are troubled rest with us, when the Lord Jesus shall be revealed from heaven with his mighty angels,
And, lo, the angel of the Lord came upon them, and the glory of the Lord shone round about them: and they were sore afraid.
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.
And I saw heaven opened, and behold a white horse; and he that sat upon him was called Faithful and True, and in righteousness he doth judge and make war.
When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory:
And without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the Spirit, seen of angels, preached unto the Gentiles, believed on in the world, received up into glory.
Hereafter shall the Son of man sit on the right hand of the power of God.
Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?
Verily, verily, I say unto you, He that entereth not by the door into the sheepfold, but climbeth up some other way, the same is a thief and a robber.