Hebrews 5:11
Of whom we have many things to say and difficult to declare, seeing ye are hard of hearing.
2 Peter 3:16
in almost all his epistles, speaking in them of these things, among which are some things that are hard to understand, which those that are ignorant and unstable twist, as they do also the other scriptures, unto their own destruction.
Matthew 13:15
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.
Isaiah 6:10
Make the heart of this people fat and make their ears heavy and blind their eyes that they not see with their eyes, nor hear with their ears, nor understand with their heart, nor convert and there be healing for him.
Mark 8:17-18
And as Jesus understood it, he said unto them, Why argue ye because ye have no bread? Do ye not consider nor understand? is your heart yet blind?
Mark 8:21
And he said unto them, How is it that ye do not yet understand?
Luke 24:25
Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken;
John 6:6
But he said this to prove him, for he knew what he would do.
John 16:12
I have yet many things to say unto you, but ye cannot bear them now.
Acts 28:27
for the heart of this people is waxed gross, and their ears are dull of hearing, and their eyes have they closed; lest they should see with their eyes and hear with their ears and understand with their heart and should be converted and I should heal them.
1 Kings 10:1
And when the queen of Sheba heard of the fame of Solomon concerning the name of the LORD, she came to prove him with enigmas.