Hebrews 5:11
of whom we have much to say, and hard to be explained since you are dull of hearing.
2 Peter 3:16
as also in all his letters, speaking in them of these things; in which are some things hard to be understood, which the unlearned and unstable pervert, as also they do the rest of the Scriptures, to their own destruction).
Matthew 13:15
for this people's heart has become gross, and their ears are dull of hearing, and they have closed their eyes, 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 shut their eyes; lest they see with their eyes, and hear with their ears, and understand with their hearts, and turn back, and be healed.
Mark 8:17-18
And knowing it, Jesus said to them, Why do you reason that it is because you have no loaves? Do you not yet perceive nor understand? Have you still hardened your heart?
Mark 8:21
And He said to them, How do you not understand?
Luke 24:25
And He said to them, O fools and slow of heart to believe all things that the prophets spoke!
John 6:6
And He said this to test him, for He Himself knew what He would do.
John 16:12
I have yet many things to say to you, but you cannot bear them now.
Acts 28:27
For the heart of this people was fattened, and they have heard with their ears dully; and they closed their eyes; lest at any time 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 the queen of Sheba heard of Solomon's fame concerning the name of Jehovah, and she came to test him with hard questions.