Romans 11:10
May their eyes be darkened, so that they cannot see; and do thou always make their backs to bend.'
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 12:39-40
The reason why they were unable to believe is given by Isaiah elsewhere, in these words--
Acts 28:26-27
'Go to this nation and say--"You will hear with your ears without ever understanding, and, though you have eyes, you will see without ever perceiving."
Romans 11:25
Brothers, for fear that you should think too highly of yourselves, I want you to recognize the truth, hitherto hidden, that the callousness which has come over Israel is only partial, and will continue only till the whole Gentile world has been gathered in.
2 Corinthians 3:14
But their minds were slow to learn. Indeed, to this very day, at the public reading of the Old Covenant, the same veil remains unlifted; only for those who are in union with Christ does it pass away.