Mark 4:12

That seeing they may see, and not perceive; and hearing they may hear, and not understand; lest at any time they should be converted, and their sins should be forgiven them.

Isaiah 6:9-10

And he said, Go, and tell this people, Hear ye indeed, but understand not; and see ye indeed, but perceive not.

Jeremiah 5:21

Hear now this, O foolish people, and without understanding; who have eyes, and see not; who have ears, and hear not:

Deuteronomy 29:4

Yet the LORD hath not given you a heart to perceive, and eyes to see, and ears to hear, to this day.

Jeremiah 31:18-20

I have surely heard Ephraim bemoaning himself thus; Thou hast chastised me, and I was chastised, as a bullock unaccustomed to the yoke: turn thou me, and I shall be turned; for thou art the LORD my God.

Matthew 13:14-15

And in them is fulfilled the prophecy of Isaiah, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive:

Luke 8:10

And he said, To you it is given to know the mysteries of the kingdom of God: but to others in parables; that seeing they may not see, and hearing they may not understand.

Isaiah 44:18

They have not known nor understood: for he hath shut their eyes, that they cannot see; and their hearts, that they cannot understand.

Ezekiel 12:2

Son of man, thou dwellest in the midst of a rebellious house, who have eyes to see, and see not; they have ears to hear, and hear not: for they are a rebellious house.

Ezekiel 18:27-32

Again, when a wicked man turneth away from his wickedness that he hath committed, and doeth that which is lawful and right, he shall save his soul alive.

John 12:37-41

But though he had done so many miracles before them, yet they believed not on him:

Acts 3:19

Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord,

Acts 28:25-27

And when they agreed not among themselves, they departed, after Paul had spoken one word, Well spoke the Holy Spirit by Isaiah the prophet to our fathers,

Romans 11:8-10

(According as it is written, God hath given them the spirit of slumber, eyes that they should not see, and ears that they should not hear;) to this day.

2 Timothy 2:25

In meekness instructing those that oppose themselves; if God perhaps will give them repentance to the acknowledging of the truth:

Hebrews 6:6

If they shall fall away, to renew them again to repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.

Treasury of Scripture Knowledge

Summary

That seeing they may see, and not perceive; and hearing they may hear, and not understand; lest at any time they should be converted, and their sins should be forgiven them.

General references

Bible References

That seeing

Deuteronomy 29:4
Yet the LORD hath not given you a heart to perceive, and eyes to see, and ears to hear, to this day.
Isaiah 6:9
And he said, Go, and tell this people, Hear ye indeed, but understand not; and see ye indeed, but perceive not.
Isaiah 44:18
They have not known nor understood: for he hath shut their eyes, that they cannot see; and their hearts, that they cannot understand.
Jeremiah 5:21
Hear now this, O foolish people, and without understanding; who have eyes, and see not; who have ears, and hear not:
Matthew 13:14
And in them is fulfilled the prophecy of Isaiah, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive:
Luke 8:10
And he said, To you it is given to know the mysteries of the kingdom of God: but to others in parables; that seeing they may not see, and hearing they may not understand.
John 12:37
But though he had done so many miracles before them, yet they believed not on him:
Acts 28:25
And when they agreed not among themselves, they departed, after Paul had spoken one word, Well spoke the Holy Spirit by Isaiah the prophet to our fathers,
Romans 11:8
(According as it is written, God hath given them the spirit of slumber, eyes that they should not see, and ears that they should not hear;) to this day.

Be converted

Jeremiah 31:18
I have surely heard Ephraim bemoaning himself thus; Thou hast chastised me, and I was chastised, as a bullock unaccustomed to the yoke: turn thou me, and I shall be turned; for thou art the LORD my God.
Ezekiel 18:27
Again, when a wicked man turneth away from his wickedness that he hath committed, and doeth that which is lawful and right, he shall save his soul alive.
Acts 3:19
Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord,
2 Timothy 2:25
In meekness instructing those that oppose themselves; if God perhaps will give them repentance to the acknowledging of the truth:
Hebrews 6:6
If they shall fall away, to renew them again to repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.

General references

Proverbs 28:5
Evil men understand not judgment: but they that seek the LORD understand all things.