John 3:12

if you don't believe when I tell you what is plain, how should you believe, if I tell you of things more sublime?

John 1:1-14

In the beginning was the Logos, and the Logos was with God, and the Logos was God.

John 3:3

Jesus answered him, I declare unto thee, except a man be born again, he cannot see the kingdom of God.

John 3:5

Jesus answered, I tell thee, except a man be renewed by the spiritual baptism, he cannot enter into the kingdom of God.

John 3:8

the wind bloweth where it listeth, and you hear the sound thereof, but cannot tell whence it comes, or whither it goes: such is the change in every one that is renewed by the spirit.

John 3:13-17

for no man hath penetrated into the secrets of heaven, but he that came down from heaven, even the son of man, who is in heaven.

John 3:31-36

but I must decline. he that cometh from above, is above all: he that is from the earth, is earthly, and his language is likewise earthly: he that cometh from heaven is above all.

1 Corinthians 2:7-9

but we explain that mysterious plan of divine wisdom, which God had contriv'd before the ages, for our glory:

1 Corinthians 3:1-2

However, I could not speak to you, my brethren, as to the spiritual, or as to the dispassionate, but as to novices in christianity.

1 Timothy 3:16

the mystery of piety is the pillar and basts of truth; and certainly most extraordinary. God has appear'd in the flesh, been justified by the spirit, seen by angels, proclaim'd to the Gentiles, believ'd by the world, and assum'd into glory.

Hebrews 5:11

On this head we have many things to say, not easily to be comprehended, because of your prejudices.

1 Peter 2:1-3

Renouncing therefore every kind of malice, and knavery, hypocrisy, envy, and detraction, as new-born infants desire that mystical milk,

1 John 4:10

and what heightens his love, was this, that it was not we who first loved God, but it was he that first loved us, and sent his son to expiate 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 answered him, I declare unto thee, except a man be born again, he cannot see the kingdom of God.
1 Corinthians 3:1
However, I could not speak to you, my brethren, as to the spiritual, or as to the dispassionate, but as to novices in christianity.
Hebrews 5:11
On this head we have many things to say, not easily to be comprehended, because of your prejudices.
1 Peter 2:1
Renouncing therefore every kind of malice, and knavery, hypocrisy, envy, and detraction, as new-born infants desire that mystical milk,

Heavenly

John 3:13
for no man hath penetrated into the secrets of heaven, but he that came down from heaven, even the son of man, who is in heaven.
John 1:1
In the beginning was the Logos, and the Logos was with God, and the Logos was God.
1 Corinthians 2:7
but we explain that mysterious plan of divine wisdom, which God had contriv'd before the ages, for our glory:
1 Timothy 3:16
the mystery of piety is the pillar and basts of truth; and certainly most extraordinary. God has appear'd in the flesh, been justified by the spirit, seen by angels, proclaim'd to the Gentiles, believ'd by the world, and assum'd into glory.
1 John 4:10
and what heightens his love, was this, that it was not we who first loved God, but it was he that first loved us, and sent his son to expiate our sins.