Romans 1:21

inasmuch as when they knew God, they glorified him not as God, neither were thankful: but waxed full of vanities in their imaginations. And their foolish hearts were blinded.

Jeremiah 2:5

Thus sayeth the LORD unto you, "What unfaithfulness found your fathers in me, that they went so far away from me, falling to lightness, and being so vain?

Ephesians 4:17-18

This I say, therefore, and testify in the Lord, that ye henceforth walk not as other gentiles walk; in vanity of their mind,

2 Kings 17:15

And they refused his ordinances and his covenant that he had made with their fathers, and the witness which he had witnessed to them and followed vanity and became vain, like to the heathen that were round about them, of which the LORD had charged them, that they should not do like them.

Romans 1:19

Seeing what may be known of God, that same is manifest among them: For God did show it unto them.

Revelation 14:7

saying with a loud voice, "Fear God and give honour to him, for the hour of his judgment is come: and worship him, that made heaven and earth, and the sea, and fountains of water."

Genesis 6:5

And when the LORD saw that the wickedness of man was increased upon the earth, and that all the imagination and thoughts of his heart was only evil continually,

Genesis 8:21

And the LORD smelled a sweet savour and said in his heart, "I will henceforth no more curse the earth for man's sake, for the imagination of man's heart is evil even from the very youth of him. Moreover I will not destroy from henceforth all that liveth as I have done.

Deuteronomy 28:29

And thou shalt grope at noonday as the blind gropeth in darkness, and shalt not come to the right way. And thou shalt suffer violence and wrong all thy life long, and no man shall help thee.

Psalm 50:23

Whoso offereth me thanks and praise, he honoureth me: and to him that ordereth his conversation right, will I show the salvation of God."

Psalm 81:12

So I gave them up unto their own hearts' lust, and let them follow their own imaginations.

Psalm 86:9

All nations whom thou hast made shall come and worship before thee, O LORD, and shall glorify thy name.

Ecclesiastes 7:29

Lo, this only have I found, that God made man just and right, but they seek divers subtleties.

Isaiah 44:9-20

All carvers of Images are but vain, and the carved images that they love can do no good. They must bear record themselves, that seeing they can neither see nor understand they shall be confounded.

Isaiah 60:2

For behold, darkness shall cover the earth, and a thick mist the nations. But the LORD shall rise as the sun over thee, and his glory shall be seen upon thee.

Jeremiah 10:3-8

Yea all the customs and laws of the Gentiles are nothing but vanity. They hew down a tree in the wood with the hands of the workman, and fashion it with the axe;

Jeremiah 10:14-15

His wisdom maketh all men fools. And confounded be all casters of images, for that they cast is but a vain thing, and hath no life.

Jeremiah 16:19

O LORD, my strength, my power, and refuge in time of trouble! The Gentiles shall come unto thee from the ends of the world, and say, "Verily our fathers have cleaved unto lies, their Idols are but vain and unprofitable.

Hosea 2:8

And she did not know that I gave her corn, and wine, and oil, and multiplied her silver and gold: which they bestowed upon Baal.

Habakkuk 1:15-16

They take up all with their angle, they catch it in their net, and gather it in their yarn: whereof they rejoice and are glad.

Luke 17:15-18

And one of them, when he saw that he was cleansed, turned back again, and with a loud voice praised God,

John 3:19

And this is the condemnation: that light is come into the world, and the men have loved darkness more than light, because their deeds were evil.

Romans 1:28

And as it seemed not good unto them to be a known of God, even so God delivered them up unto a lewd mind, that they should do those things which were not comely,

Romans 11:10

Let their eyes be blinded that they see not: and ever bow down their backs."

Romans 15:9

And let the gentiles praise God for his mercy. As it is written, "For this cause I will praise thee among the gentiles, and sing in thy name."

2 Timothy 3:2

For the men shall be lovers of their own selves, covetous, boasters, proud, cursed speakers, disobedient to father and mother, unthankful, unholy,

1 Peter 1:18

Forasmuch as ye know how that ye were not redeemed with corruptible gold and silver from your vain conversation, which ye received by the traditions of the fathers,

1 Peter 2:9

But ye are a chosen generation, a royal priesthood, a holy nation, and a peculiar people, that ye should show the virtues of him that called you out of darkness into his marvelous light,

Revelation 15:4

Who shall not fear, o Lord, and glorify thy name? For thou only art holy, and all gentiles shall come and worship before thee, for thy judgments are made manifest."

Acts 26:18

to open their eyes that they might turn from darkness unto light, and from the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith in me.'

Treasury of Scripture Knowledge

Summary

Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.

Bible References

When

Romans 1:19
Seeing what may be known of God, that same is manifest among them: For God did show it unto them.
John 3:19
And this is the condemnation: that light is come into the world, and the men have loved darkness more than light, because their deeds were evil.

They glorified

Romans 15:9
And let the gentiles praise God for his mercy. As it is written, "For this cause I will praise thee among the gentiles, and sing in thy name."
Psalm 50:23
Whoso offereth me thanks and praise, he honoureth me: and to him that ordereth his conversation right, will I show the salvation of God."
Psalm 86:9
All nations whom thou hast made shall come and worship before thee, O LORD, and shall glorify thy name.
Hosea 2:8
And she did not know that I gave her corn, and wine, and oil, and multiplied her silver and gold: which they bestowed upon Baal.
Habakkuk 1:15
They take up all with their angle, they catch it in their net, and gather it in their yarn: whereof they rejoice and are glad.
Luke 17:15
And one of them, when he saw that he was cleansed, turned back again, and with a loud voice praised God,
2 Timothy 3:2
For the men shall be lovers of their own selves, covetous, boasters, proud, cursed speakers, disobedient to father and mother, unthankful, unholy,
Revelation 14:7
saying with a loud voice, "Fear God and give honour to him, for the hour of his judgment is come: and worship him, that made heaven and earth, and the sea, and fountains of water."
Revelation 15:4
Who shall not fear, o Lord, and glorify thy name? For thou only art holy, and all gentiles shall come and worship before thee, for thy judgments are made manifest."

But became

Genesis 6:5
And when the LORD saw that the wickedness of man was increased upon the earth, and that all the imagination and thoughts of his heart was only evil continually,
Genesis 8:21
And the LORD smelled a sweet savour and said in his heart, "I will henceforth no more curse the earth for man's sake, for the imagination of man's heart is evil even from the very youth of him. Moreover I will not destroy from henceforth all that liveth as I have done.
2 Kings 17:15
And they refused his ordinances and his covenant that he had made with their fathers, and the witness which he had witnessed to them and followed vanity and became vain, like to the heathen that were round about them, of which the LORD had charged them, that they should not do like them.
Psalm 81:12
So I gave them up unto their own hearts' lust, and let them follow their own imaginations.
Ecclesiastes 7:29
Lo, this only have I found, that God made man just and right, but they seek divers subtleties.
Isaiah 44:9
All carvers of Images are but vain, and the carved images that they love can do no good. They must bear record themselves, that seeing they can neither see nor understand they shall be confounded.
Jeremiah 2:5
Thus sayeth the LORD unto you, "What unfaithfulness found your fathers in me, that they went so far away from me, falling to lightness, and being so vain?
Jeremiah 10:3
Yea all the customs and laws of the Gentiles are nothing but vanity. They hew down a tree in the wood with the hands of the workman, and fashion it with the axe;
Jeremiah 16:19
O LORD, my strength, my power, and refuge in time of trouble! The Gentiles shall come unto thee from the ends of the world, and say, "Verily our fathers have cleaved unto lies, their Idols are but vain and unprofitable.
Ephesians 4:17
This I say, therefore, and testify in the Lord, that ye henceforth walk not as other gentiles walk; in vanity of their mind,
1 Peter 1:18
Forasmuch as ye know how that ye were not redeemed with corruptible gold and silver from your vain conversation, which ye received by the traditions of the fathers,

Their foolish

Romans 11:10
Let their eyes be blinded that they see not: and ever bow down their backs."
Deuteronomy 28:29
And thou shalt grope at noonday as the blind gropeth in darkness, and shalt not come to the right way. And thou shalt suffer violence and wrong all thy life long, and no man shall help thee.
Isaiah 60:2
For behold, darkness shall cover the earth, and a thick mist the nations. But the LORD shall rise as the sun over thee, and his glory shall be seen upon thee.
Acts 26:18
to open their eyes that they might turn from darkness unto light, and from the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith in me.'
1 Peter 2:9
But ye are a chosen generation, a royal priesthood, a holy nation, and a peculiar people, that ye should show the virtues of him that called you out of darkness into his marvelous light,

General references

Psalm 94:11
The LORD knoweth the thoughts of men, that they are but vain.
Isaiah 40:21
Know ye not this? Heard ye never of it? Hath it not been preached unto you since the beginning? Have ye not been informed of this since the foundation of the earth was laid?
Jeremiah 33:18
neither shall the priests and Levites want one to offer always before me burnt offerings, to kindle the meat offerings, and to prepare the sacrifices."
James 4:17
Therefore to him that knoweth how to do good, and doth it not: to him, it is sin.