John 3:12

If you have no belief when my words are about the things of earth, how will you have belief if my words are about the things of heaven?

John 1:1-14

From the first he was the Word, and the Word was in relation with God and was God.

John 3:3

Jesus said to him, Truly, I say to you, Without a new birth no man is able to see the kingdom of God.

John 3:5

Jesus said in answer, Truly, I say to you, If a man's birth is not from water and from the Spirit, it is not possible for him to go into the kingdom of God.

John 3:8

The wind goes where its pleasure takes it, and the sound of it comes to your ears, but you are unable to say where it comes from and where it goes: so it is with everyone whose birth is from the Spirit.

John 3:13-17

And no one has ever gone up to heaven but he who came down from heaven, the Son of man.

John 3:31-36

He who comes from heaven is greater than all others: he who comes from earth is of the earth, and of the earth are his words: he who comes from heaven is over all.

1 Corinthians 2:7-9

But we give the news of the secret wisdom of God, which he had kept in store before the world came into existence, for our glory;

1 Corinthians 3:1-2

And the teaching I gave you, my brothers, was such as I was able to give, not to those who have the Spirit, but to those who are still in the flesh, even to children in Christ.

1 Timothy 3:16

And without argument, great is the secret of religion: He who was seen in the flesh, who was given God's approval in the spirit, was seen by the angels, of whom the good news was given among the nations, in whom the world had faith, who was taken up in glory.

Hebrews 5:11

Of whom we have much to say which it is hard to make clear, because you are slow of hearing.

1 Peter 2:1-3

So putting away all wrongdoing, and all tricks and deceits and envies and evil talk,

1 John 4:10

And this is love, not that we had love for God, but that he had love for us, and sent his Son to be an offering for our sins.

Treasury of Scripture Knowledge

Summary

If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you of heavenly things?

Bible References

Earthly

John 3:3
Jesus said to him, Truly, I say to you, Without a new birth no man is able to see the kingdom of God.
1 Corinthians 3:1
And the teaching I gave you, my brothers, was such as I was able to give, not to those who have the Spirit, but to those who are still in the flesh, even to children in Christ.
Hebrews 5:11
Of whom we have much to say which it is hard to make clear, because you are slow of hearing.
1 Peter 2:1
So putting away all wrongdoing, and all tricks and deceits and envies and evil talk,

Heavenly

John 3:13
And no one has ever gone up to heaven but he who came down from heaven, the Son of man.
John 1:1
From the first he was the Word, and the Word was in relation with God and was God.
1 Corinthians 2:7
But we give the news of the secret wisdom of God, which he had kept in store before the world came into existence, for our glory;
1 Timothy 3:16
And without argument, great is the secret of religion: He who was seen in the flesh, who was given God's approval in the spirit, was seen by the angels, of whom the good news was given among the nations, in whom the world had faith, who was taken up in glory.
1 John 4:10
And this is love, not that we had love for God, but that he had love for us, and sent his Son to be an offering for our sins.

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain