Mark 4:12

that seeing they may see and not perceive, and hearing they may hear and not understand, lest they may turn, and the sins may be forgiven them.'

Isaiah 6:9-10

And He saith, 'Go, and thou hast said to this people, Hear ye -- to hear, and ye do not understand, And see ye -- to see, and ye do not know.

Jeremiah 5:21

Hear ye, I pray you, this, O people, foolish and without heart, Eyes they have, and they see not, Ears they have, and they hear not.

Deuteronomy 29:4

and Jehovah hath not given to you a heart to know, and eyes to see, and ears to hear, till this day,

Jeremiah 31:18-20

I have surely heard Ephraim bemoaning himself, 'Thou hast chastised me, And I am chastised, as a heifer not taught, Turn me back, and I turn back, For thou art Jehovah my God.

Matthew 13:14-15

and fulfilled on them is the prophecy of Isaiah, that saith, With hearing ye shall hear, and ye shall not understand, and seeing ye shall see, and ye shall not perceive,

Luke 8:10

And he said, 'To you it hath been given to know the secrets of the reign of God, and to the rest in similes; that seeing they may not see, and hearing they may not understand.

Isaiah 44:18

They have not known, nor do they understand, For He hath daubed their eyes from seeing, Their heart from acting wisely.

Ezekiel 12:2

Son of man, in the midst of the rebellious house thou art dwelling, that have eyes to see, and they have not seen; ears they have to hear, and they have not heard; for a rebellious house are they.

Ezekiel 18:27-32

And in the turning back of the wicked From his wickedness that he hath done, And he doth judgment and righteousness, He his soul doth keep alive.

John 12:37-41

yet he having done so many signs before them, they were not believing in him,

Acts 3:19

reform ye, therefore, and turn back, for your sins being blotted out, that times of refreshing may come from the presence of the Lord,

Acts 28:25-27

And not being agreed with one another, they were going away, Paul having spoken one word -- 'Well did the Holy Spirit speak through Isaiah the prophet unto our fathers,

Romans 11:8-10

according as it hath been written, 'God gave to them a spirit of deep sleep, eyes not to see, and ears not to hear,' -- unto this very day,

2 Timothy 2:25

in meekness instructing those opposing -- if perhaps God may give to them repentance to an acknowledging of the truth,

Hebrews 6:6

and having fallen away, again to renew them to reformation, having crucified again to themselves the Son of God, and exposed to public 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
and Jehovah hath not given to you a heart to know, and eyes to see, and ears to hear, till this day,
Isaiah 6:9
And He saith, 'Go, and thou hast said to this people, Hear ye -- to hear, and ye do not understand, And see ye -- to see, and ye do not know.
Isaiah 44:18
They have not known, nor do they understand, For He hath daubed their eyes from seeing, Their heart from acting wisely.
Jeremiah 5:21
Hear ye, I pray you, this, O people, foolish and without heart, Eyes they have, and they see not, Ears they have, and they hear not.
Matthew 13:14
and fulfilled on them is the prophecy of Isaiah, that saith, With hearing ye shall hear, and ye shall not understand, and seeing ye shall see, and ye shall not perceive,
Luke 8:10
And he said, 'To you it hath been given to know the secrets of the reign of God, and to the rest in similes; that seeing they may not see, and hearing they may not understand.
John 12:37
yet he having done so many signs before them, they were not believing in him,
Acts 28:25
And not being agreed with one another, they were going away, Paul having spoken one word -- 'Well did the Holy Spirit speak through Isaiah the prophet unto our fathers,
Romans 11:8
according as it hath been written, 'God gave to them a spirit of deep sleep, eyes not to see, and ears not to hear,' -- unto this very day,

Be converted

Jeremiah 31:18
I have surely heard Ephraim bemoaning himself, 'Thou hast chastised me, And I am chastised, as a heifer not taught, Turn me back, and I turn back, For thou art Jehovah my God.
Ezekiel 18:27
And in the turning back of the wicked From his wickedness that he hath done, And he doth judgment and righteousness, He his soul doth keep alive.
Acts 3:19
reform ye, therefore, and turn back, for your sins being blotted out, that times of refreshing may come from the presence of the Lord,
2 Timothy 2:25
in meekness instructing those opposing -- if perhaps God may give to them repentance to an acknowledging of the truth,
Hebrews 6:6
and having fallen away, again to renew them to reformation, having crucified again to themselves the Son of God, and exposed to public shame.

General references

Proverbs 28:5
Evil men understand not judgment, And those seeking Jehovah understand all.