Matthew 12:34
You brood of vipers! how can you, evil as you are, say anything good? For what fills the heart will rise to the lips.
Matthew 13:14-15
And in them is being fulfilled that prophecy of Isaiah which says--'You will hear with your ears without ever understanding, And, though you have eyes, you will see without ever perceiving,
John 5:44
How can you believe in me, when you receive honor from one another and do not desire the honor which comes from the only God?
John 8:43
How is it that you do not understand what I say? It is because you cannot bear to listen to my Message.
John 12:39-40
The reason why they were unable to believe is given by Isaiah elsewhere, in these words--
Acts 14:16
In bygone times he permitted all the nations to go their own ways.
Romans 1:21-23
Because, although they learned to know God, yet they did not offer him as God either praise or thanksgiving. Their speculations about him proved futile, and their undiscerning minds were darkened.
Romans 1:28
Then, as they would not keep God before their minds, God abandoned them to depraved thoughts, so that they did all kinds of shameful things.
Romans 11:8-10
The rest grew callous; as Scripture says--'God has given them a deadness of mind--eyes that are not to see and ears that are not to hear--and it is so to this very day.'
2 Corinthians 4:3-4
And, even if the Good News that we bring is veiled, it is veiled only in the case of those who are on the path to Ruin--
2 Thessalonians 2:9-12
For at the Coming of the Lord there will be great activity on the part of Satan, in the form of all kinds of deceptive miracles, signs, and marvels, as well as of wicked attempts to delude--
2 Peter 2:14
They have eyes only for adulteresses, eyes never tired of sin; they entice weak souls; their minds are trained to covet; they live under a curse.