Matthew 13:15

For this people's mind is stupefied, their hearing has become dull, and their eyes they have closed; to prevent their ever seeing with their eyes, or hearing with their ears, or understanding with their minds, and turning back, so that I might heal them.'

Hebrews 5:11

Concerning Him we have much to say, and much that it would be difficult to make clear to you, since you have become so dull of apprehension.

John 8:43-44

How is it you do not understand me when I speak? It is because you cannot bear to listen to my words.

2 Timothy 4:4

and will turn away from listening to the truth and will turn aside to fables.

Mark 4:12

that "'They may look and look but not see, and listen and listen but not understand, lest perchance they should return and be pardoned.'"

Acts 3:19

Repent, therefore, and reform your lives, so that the record of your sins may be cancelled, and that there may come seasons of revival from the Lord,

Acts 7:57

Upon this, with a loud outcry they stopped their ears, rushed upon Stephen in a body,

2 Thessalonians 2:10-11

and by every kind of wicked deception for those who are on the way to perdition because they did not welcome into their hearts the love of the truth, so that they might be saved.

2 Timothy 2:25-26

He must speak in a gentle tone when correcting the errors of opponents, in the hope that God will at last give them repentance, for them to come to a full knowledge of the truth

Hebrews 6:4-6

For it is impossible, in the case of those who have once for all been enlightened, and have tasted the sweetness of the heavenly gift, and have been made partakers of the Holy Spirit,

Revelation 22:2

On either side of the river, midway between it and the main street of the city, was the Tree of Life. It produced twelve kinds of fruit, yielding a fresh crop month by month, and the leaves of the tree served as medicine for the nations.

Treasury of Scripture Knowledge

Summary

For this people's heart 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 should understand with their heart, and should be converted, and I should heal them.

General references

Bible References

Ears

John 8:43
How is it you do not understand me when I speak? It is because you cannot bear to listen to my words.
Acts 7:57
Upon this, with a loud outcry they stopped their ears, rushed upon Stephen in a body,
2 Timothy 4:4
and will turn away from listening to the truth and will turn aside to fables.
Hebrews 5:11
Concerning Him we have much to say, and much that it would be difficult to make clear to you, since you have become so dull of apprehension.

And should be

Acts 3:19
Repent, therefore, and reform your lives, so that the record of your sins may be cancelled, and that there may come seasons of revival from the Lord,
2 Timothy 2:25
He must speak in a gentle tone when correcting the errors of opponents, in the hope that God will at last give them repentance, for them to come to a full knowledge of the truth
Hebrews 6:4
For it is impossible, in the case of those who have once for all been enlightened, and have tasted the sweetness of the heavenly gift, and have been made partakers of the Holy Spirit,

And i

Mark 4:12
that "'They may look and look but not see, and listen and listen but not understand, lest perchance they should return and be pardoned.'"
Revelation 22:2
On either side of the river, midway between it and the main street of the city, was the Tree of Life. It produced twelve kinds of fruit, yielding a fresh crop month by month, and the leaves of the tree served as medicine for the nations.

General references

Matthew 24:39
nor did they realise any danger till the Deluge came and swept them all away; so will it be at the Coming of the Son of Man.