Ephesians 4:18

which are overspread with darkness, and averse to a religious life, thro' their innate ignorance and obduracy:

Ephesians 2:12

that at that time ye were without all knowledge of the Messiah, being aliens from the common-wealth of Israel, and strangers to the covenants of promise, having no hope, and living in the world without any true knowledge of God.

Galatians 4:8

When you did not know God, you did service to those, who in reality are no Gods; but now that you know God,

1 Thessalonians 4:5

person unsullied by the vices of the Gentiles, who know not God:

Acts 17:30

God has been pleas'd to over-look this state of ignorance: but now he enjoins all men every where to repent:

Romans 1:21-23

because when they knew God, they did not with gratitude glorify him as God, but their reasoning became extravagance, and their minds, void of judgment, were involv'd in darkness.

Romans 11:25

I would not, brethren, have you ignorant of this secret, (for fear you should presume too much on your selves) that blindness has fallen upon a part of Israel, until the time when the Gentiles shall be fully come in.

Matthew 13:15

for the heart of this people is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes, and hear with their ears, and understand with their heart, and should be converted, and I should heal them."

Mark 3:5

then he looking with indignation at those about him, being concern'd at their disingenuous perverse temper, he said to the man, stretch out your hand, which he did, and his hand become sound.

John 12:40

and hardned their heart; that they should not see with their eyes, nor understand with their heart, and be converted, and I should heal them."

Acts 26:17-18

by delivering you from this people, and from the Gentiles to whom I now send thee, to open their eyes,

Romans 1:28

As they did not seek the favour of God, by worshipping him, God gave them over to a depraved sense, to act unworthy of human nature;

Romans 2:19

you think you are a guide to the blind, a light to those who are in darkness,

Romans 8:7-8

because a sensual disposition of mind is averse to God: for it is not subject to the divine law, nor indeed can it be.

1 Corinthians 1:21

for whereas the world, with all their learning, did not distinguish the characters of his divine wisdom, in his works, it pleased God to save those who believe, by preaching, which they counted folly.

2 Corinthians 3:14

besides, their minds were greatly prejudiced: for that very veil would still have obstructed the understanding of the old testament, unless it had been taken away by Christ.

2 Corinthians 4:4

to those unbelievers, whose minds the God of this world has so blinded, that the glorious lustre of the gospel of Christ, who is the image of God, does not enlighten them.

Colossians 1:21

You then that formerly were alienated from God, and were enemies by your imaginations and wicked practices, even you has Jesus Christ now reconciled to the body of his church,

James 4:4

Degenerate race, don't you know that friendship with vice is hostility against heaven. he that is a friend to the vicious world, is an enemy to God.

1 John 2:11

but he that hates his brother, is in darkness, he walks in darkness, and knows not whither he is going, because the darkness hath blinded his eyes.

Treasury of Scripture Knowledge

Summary

Having the understanding darkened, being alienated from the life of God through the ignorance that is in them, because of the blindness of their heart:

Bible References

The understanding

Acts 17:30
God has been pleas'd to over-look this state of ignorance: but now he enjoins all men every where to repent:
Acts 26:17
by delivering you from this people, and from the Gentiles to whom I now send thee, to open their eyes,
Romans 1:21
because when they knew God, they did not with gratitude glorify him as God, but their reasoning became extravagance, and their minds, void of judgment, were involv'd in darkness.
1 Corinthians 1:21
for whereas the world, with all their learning, did not distinguish the characters of his divine wisdom, in his works, it pleased God to save those who believe, by preaching, which they counted folly.
2 Corinthians 4:4
to those unbelievers, whose minds the God of this world has so blinded, that the glorious lustre of the gospel of Christ, who is the image of God, does not enlighten them.
Galatians 4:8
When you did not know God, you did service to those, who in reality are no Gods; but now that you know God,
1 Thessalonians 4:5
person unsullied by the vices of the Gentiles, who know not God:

Alienated

Ephesians 2:12
that at that time ye were without all knowledge of the Messiah, being aliens from the common-wealth of Israel, and strangers to the covenants of promise, having no hope, and living in the world without any true knowledge of God.
Romans 8:7
because a sensual disposition of mind is averse to God: for it is not subject to the divine law, nor indeed can it be.
Galatians 4:8
When you did not know God, you did service to those, who in reality are no Gods; but now that you know God,
Colossians 1:21
You then that formerly were alienated from God, and were enemies by your imaginations and wicked practices, even you has Jesus Christ now reconciled to the body of his church,
1 Thessalonians 4:5
person unsullied by the vices of the Gentiles, who know not God:
James 4:4
Degenerate race, don't you know that friendship with vice is hostility against heaven. he that is a friend to the vicious world, is an enemy to God.

Because

Romans 1:21
because when they knew God, they did not with gratitude glorify him as God, but their reasoning became extravagance, and their minds, void of judgment, were involv'd in darkness.
Romans 2:19
you think you are a guide to the blind, a light to those who are in darkness,
1 John 2:11
but he that hates his brother, is in darkness, he walks in darkness, and knows not whither he is going, because the darkness hath blinded his eyes.