Mark 4:12

That seeing they might see, and not know; and hearing they might hear, and not understand; lest they turn back, and their sins be remitted to them.

Isaiah 6:9-10

And he will say, Go, and say to this people, Hearing, hear ye, and ye shall not understand; and seeing, see ye, and ye shall not know.

Jeremiah 5:21

Hear now this, O foolish people, and no heart; eyes to them and they will not see; and ears to them, and they will not hear:

Deuteronomy 29:4

And Jehovah gave not to you an heart to know, and eyes to see, and ears to hear, even to this day.

Jeremiah 31:18-20

Hearing, I heard Ephraim being thrust away: Thou didst correct me, and I shall be corrected as a calf not being taught: turn me back and I shall be turned back, for thou Jehovah my God.

Matthew 13:14-15

And the prophecy of Esaias is filled up in them, saying, In hearing shall ye hear, and not understand; and seeing ye shall see, and not perceive.

Luke 8:10

And he said, To you it has been given to know the mysteries of the kingdom of God: and to the rest in parables; that seeing they might not see, and hearing they might not understand.

Isaiah 44:18

They will not know, and they will not discern: he spread over their eyes from seeing; their heart from considering.

Ezekiel 12:2

Son of man, thou art dwelling in the midst of a house of contradiction, which to them eyes to see, and they saw not: ears to them to hear, and they heard not: for they are a house of contradiction.

Ezekiel 18:27-32

And in the unjust one turning back from his injustice which he did; and he will do judgment and justice, he shall save his soul alive.

John 12:37-41

And he having done so many signs before them, they did not believe in him:

Acts 3:19

Therefore repent, and return, for your sins to be wiped out, so that times of refreshment might come from the face of the Lord;

Acts 28:25-27

And being at variance with one another, they were let go, Paul having said one word, That well spake the Holy Spirit by Esaias the prophet to our fathers,

Romans 11:8-10

(As has been written, God gave them the spirit of mortal pain, eyes not to see, and earn not to hear;) even to this day.

2 Timothy 2:25

In meekness instructing them being in a contrary state; lest perhaps God may give them repentance to the acknowledgment of the truth;

Hebrews 6:6

And having fallen, again to renew to repentance; crucifying to themselves the Son of God, and exposing to ignominy.

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 gave not to you an heart to know, and eyes to see, and ears to hear, even to this day.
Isaiah 6:9
And he will say, Go, and say to this people, Hearing, hear ye, and ye shall not understand; and seeing, see ye, and ye shall not know.
Isaiah 44:18
They will not know, and they will not discern: he spread over their eyes from seeing; their heart from considering.
Jeremiah 5:21
Hear now this, O foolish people, and no heart; eyes to them and they will not see; and ears to them, and they will not hear:
Matthew 13:14
And the prophecy of Esaias is filled up in them, saying, In hearing shall ye hear, and not understand; and seeing ye shall see, and not perceive.
Luke 8:10
And he said, To you it has been given to know the mysteries of the kingdom of God: and to the rest in parables; that seeing they might not see, and hearing they might not understand.
John 12:37
And he having done so many signs before them, they did not believe in him:
Acts 28:25
And being at variance with one another, they were let go, Paul having said one word, That well spake the Holy Spirit by Esaias the prophet to our fathers,
Romans 11:8
(As has been written, God gave them the spirit of mortal pain, eyes not to see, and earn not to hear;) even to this day.

Be converted

Jeremiah 31:18
Hearing, I heard Ephraim being thrust away: Thou didst correct me, and I shall be corrected as a calf not being taught: turn me back and I shall be turned back, for thou Jehovah my God.
Ezekiel 18:27
And in the unjust one turning back from his injustice which he did; and he will do judgment and justice, he shall save his soul alive.
Acts 3:19
Therefore repent, and return, for your sins to be wiped out, so that times of refreshment might come from the face of the Lord;
2 Timothy 2:25
In meekness instructing them being in a contrary state; lest perhaps God may give them repentance to the acknowledgment of the truth;
Hebrews 6:6
And having fallen, again to renew to repentance; crucifying to themselves the Son of God, and exposing to ignominy.

General references

Proverbs 28:5
Men of evil shall not understand judgment: and they seeking Jehovah shall understand all.