Mark 4:12

that, seeing, they may see, and not perceive; and, hearing, they may hear, and not understand; lest haply they should turn, and be forgiven."

Matthew 13:14-15

And to them is fulfilled the prophecy of Isaiah, which says, 'With hearing ye will hear, and will not understand; and, seeing, ye will see, and will not perceive;

Luke 8:10

And He said, "To you it has been given to know the mysteries of the Kingdom of God; but to the rest in parables; that, seeing, they may not see, and, hearing, they may not understand.

John 12:37-41

But, though He had done so many signs before them, they were not believing on Him;

Acts 3:19

Repent ye, therefore, and turn, that your sins may be blotted out, that so there may come seasons of refreshing from the presence of the Lord;

Acts 28:25-27

And, disagreeing among themselves, they were departing, when Paul uttered one declaration, "Well did the Holy Spirit speak through Isaiah, the prophet, to your fathers,

Romans 11:8-10

as it has been written, "God gave them a spirit of stupor, eyes that they should not see, and ears that they should not hear, unto this day."

2 Timothy 2:25

in meekness correcting those opposing themselves, if peradventure God should give them repentance to a full knowledge of the truth,

Hebrews 6:6

and then fell away, it is impossible to renew them again to repentance, since they are crucifying to themselves the Son of God afresh, and putting Him to 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.

Bible References

That seeing

Matthew 13:14
And to them is fulfilled the prophecy of Isaiah, which says, 'With hearing ye will hear, and will not understand; and, seeing, ye will see, and will not perceive;
Luke 8:10
And He said, "To you it has been given to know the mysteries of the Kingdom of God; but to the rest in parables; that, seeing, they may not see, and, hearing, they may not understand.
John 12:37
But, though He had done so many signs before them, they were not believing on Him;
Acts 28:25
And, disagreeing among themselves, they were departing, when Paul uttered one declaration, "Well did the Holy Spirit speak through Isaiah, the prophet, to your fathers,
Romans 11:8
as it has been written, "God gave them a spirit of stupor, eyes that they should not see, and ears that they should not hear, unto this day."

Be converted

Acts 3:19
Repent ye, therefore, and turn, that your sins may be blotted out, that so there may come seasons of refreshing from the presence of the Lord;
2 Timothy 2:25
in meekness correcting those opposing themselves, if peradventure God should give them repentance to a full knowledge of the truth,
Hebrews 6:6
and then fell away, it is impossible to renew them again to repentance, since they are crucifying to themselves the Son of God afresh, and putting Him to open shame.