Romans 1:21

because having known God, they did not glorify him as God, neither were thankful, but became vain in their imaginations, and their foolish heart was darkened.

Jeremiah 2:5

thus hath the LORD said, What iniquity have your fathers found in me that they are gone far from me and have walked after vanity and are become vain?

Ephesians 4:17-18

This I say, therefore, and require in the Lord that from now on ye not walk as the other Gentiles walk in the vanity of their own senses,

2 Kings 17:15

And they rejected his statutes and his covenant that he made with their fathers and his testimonies which he testified against them, and they followed vanity and became vain and went after the Gentiles that were round about them, concerning whom the LORD had charged them, that they should not do like them.

Romans 1:19

because that which is known of God is manifest to them; for God has showed it unto them.

Revelation 14:7

saying with a loud voice, Fear God and give glory to him, for the hour of his judgment is come; and worship him that has made the heaven and the earth and the sea and the fountains of waters.

Genesis 6:5

And GOD saw that the wickedness of man was great in the earth and that every imagination of the thoughts of his heart was only evil continually.

Genesis 8:21

And the LORD smelled a savour of rest, and the LORD said in his heart, I will not again curse the ground any more for man's sake, for the intent of man's heart is evil from his childhood; neither will I again smite any more every living thing as I have done.

Deuteronomy 28:29

And thou shalt grope at noonday as the blind grope in the darkness, and thou shalt not be prospered in thy ways; and thou shalt only be oppressed and spoiled all the days, and there shall be no one to save thee.

Psalm 50:23

Whosoever sacrifices praise glorifies me; and to him that orders his ways aright I will show the salvation of God.

Psalm 81:12

So I gave them up unto the hardness of their heart, and they walked in their own counsels.

Psalm 86:9

All the Gentiles whom thou hast made shall come and humble themselves before thee, O Lord; and shall glorify thy name.

Ecclesiastes 7:29

Behold, this only have I found: that God has made man upright, but they have sought out many perversions.

Isaiah 44:9-20

Those that make a graven image are all of them vanity; and that which is most precious to them is useful for nothing; and they are their own witnesses that they do not see, nor understand; therefore, they shall be ashamed.

Isaiah 60:2

For, behold, the darkness shall cover the earth, and gross darkness the peoples: but the LORD shall arise upon thee, and his glory shall be seen upon thee.

Jeremiah 10:3-8

For the customs of the peoples are vanity: for one cuts a tree out of the forest, the work of the hands of the workman, with the axe.

Jeremiah 10:14-15

Every man is carnal in his knowledge: let every founder be ashamed of his graven image: for his molten image is falsehood, and there is no spirit in them.

Jeremiah 16:19

O LORD, my strength, and my fortress, and my refuge in the time of the affliction; Gentiles shall come unto thee from the ends of the earth and shall say, Surely our fathers have inherited lies, vanity, and things in which there is no profit.

Hosea 2:8

For she did not recognize that I gave her the wheat and the wine and the oil and multiplied unto them the silver and the gold, with which they made Baal.

Habakkuk 1:15-16

He shall take up all of them with his hook; he shall catch them in his net and gather them in his drag: therefore, he shall rejoice and be glad.

Luke 17:15-18

Then one of them, when he saw that he was healed, turned back and with a loud voice glorified God

John 3:19

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

Romans 1:28

And even as they did not like to retain God in their knowledge, God gave them over to a perverse understanding, to do those things which are not convenient,

Romans 11:10

Let their eyes be darkened that they may not see, and bow down their back always.

Romans 15:9

but that the Gentiles glorify God by mercy; as it is written, For this cause I will confess thee among the Gentiles and sing unto thy name.

2 Timothy 3:2

For there shall be men who are lovers of their own selves, covetous, boasters, proud, evil speakers, disobedient to their parents, unthankful, impure,

1 Peter 1:18

knowing that ye have been ransomed from your vain conversation (which you received from your fathers), not with corruptible things like silver and gold,

1 Peter 2:9

But ye are the chosen generation, a royal priesthood, a holy nation, an acquired people, that ye should show forth the virtues of him who has called you out of darkness into his marvellous light.

Revelation 15:4

Who shall not fear thee, O Lord, and magnify thy name? for thou only art holy; therefore, all the Gentiles shall come and worship before thee; for thy judgments are made manifest.

Acts 26:18

to open their eyes and to turn them from darkness to light and from the power of Satan unto God, that they may receive remission of sins and inheritance among those who are sanctified by the faith that is 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
because that which is known of God is manifest to them; for God has showed it unto them.
John 3:19
And this is the condemnation, that the light is come into the world, and men loved darkness more than the light because their deeds were evil.

They glorified

Romans 15:9
but that the Gentiles glorify God by mercy; as it is written, For this cause I will confess thee among the Gentiles and sing unto thy name.
Psalm 50:23
Whosoever sacrifices praise glorifies me; and to him that orders his ways aright I will show the salvation of God.
Psalm 86:9
All the Gentiles whom thou hast made shall come and humble themselves before thee, O Lord; and shall glorify thy name.
Hosea 2:8
For she did not recognize that I gave her the wheat and the wine and the oil and multiplied unto them the silver and the gold, with which they made Baal.
Habakkuk 1:15
He shall take up all of them with his hook; he shall catch them in his net and gather them in his drag: therefore, he shall rejoice and be glad.
Luke 17:15
Then one of them, when he saw that he was healed, turned back and with a loud voice glorified God
2 Timothy 3:2
For there shall be men who are lovers of their own selves, covetous, boasters, proud, evil speakers, disobedient to their parents, unthankful, impure,
Revelation 14:7
saying with a loud voice, Fear God and give glory to him, for the hour of his judgment is come; and worship him that has made the heaven and the earth and the sea and the fountains of waters.
Revelation 15:4
Who shall not fear thee, O Lord, and magnify thy name? for thou only art holy; therefore, all the Gentiles shall come and worship before thee; for thy judgments are made manifest.

But became

Genesis 6:5
And GOD saw that the wickedness of man was great in the earth and that every imagination of the thoughts of his heart was only evil continually.
Genesis 8:21
And the LORD smelled a savour of rest, and the LORD said in his heart, I will not again curse the ground any more for man's sake, for the intent of man's heart is evil from his childhood; neither will I again smite any more every living thing as I have done.
2 Kings 17:15
And they rejected his statutes and his covenant that he made with their fathers and his testimonies which he testified against them, and they followed vanity and became vain and went after the Gentiles that were round about them, concerning whom the LORD had charged them, that they should not do like them.
Psalm 81:12
So I gave them up unto the hardness of their heart, and they walked in their own counsels.
Ecclesiastes 7:29
Behold, this only have I found: that God has made man upright, but they have sought out many perversions.
Isaiah 44:9
Those that make a graven image are all of them vanity; and that which is most precious to them is useful for nothing; and they are their own witnesses that they do not see, nor understand; therefore, they shall be ashamed.
Jeremiah 2:5
thus hath the LORD said, What iniquity have your fathers found in me that they are gone far from me and have walked after vanity and are become vain?
Jeremiah 10:3
For the customs of the peoples are vanity: for one cuts a tree out of the forest, the work of the hands of the workman, with the axe.
Jeremiah 16:19
O LORD, my strength, and my fortress, and my refuge in the time of the affliction; Gentiles shall come unto thee from the ends of the earth and shall say, Surely our fathers have inherited lies, vanity, and things in which there is no profit.
Ephesians 4:17
This I say, therefore, and require in the Lord that from now on ye not walk as the other Gentiles walk in the vanity of their own senses,
1 Peter 1:18
knowing that ye have been ransomed from your vain conversation (which you received from your fathers), not with corruptible things like silver and gold,

Their foolish

Romans 11:10
Let their eyes be darkened that they may not see, and bow down their back always.
Deuteronomy 28:29
And thou shalt grope at noonday as the blind grope in the darkness, and thou shalt not be prospered in thy ways; and thou shalt only be oppressed and spoiled all the days, and there shall be no one to save thee.
Isaiah 60:2
For, behold, the darkness shall cover the earth, and gross darkness the peoples: but the LORD shall arise upon thee, and his glory shall be seen upon thee.
Acts 26:18
to open their eyes and to turn them from darkness to light and from the power of Satan unto God, that they may receive remission of sins and inheritance among those who are sanctified by the faith that is in me.
1 Peter 2:9
But ye are the chosen generation, a royal priesthood, a holy nation, an acquired people, that ye should show forth the virtues of him who has called you out of darkness into his marvellous light.

General references

Psalm 94:11
The LORD knows the thoughts of man, that they are vanity.
Isaiah 40:21
Have ye not known? Have ye not heard? Has it not been told you from the beginning? Have ye not been taught since the land was founded?
Jeremiah 33:18
neither shall the priests the Levites lack a man before me to offer burnt offerings and to kindle grain offerings and to do sacrifice continually.
James 4:17
Therefore sin is still in the one that knows to do good and does not do it.