Luke 24:25

So he said to them, "You foolish people -- how slow of heart to believe all that the prophets have spoken!

Mark 7:18

He said to them, "Are you so foolish? Don't you understand that whatever goes into a person from outside cannot defile him?

Mark 8:17-18

When he learned of this, Jesus said to them, "Why are you arguing about having no bread? Do you still not see or understand? Have your hearts been hardened?

Mark 9:19

He answered them, "You unbelieving generation! How much longer must I be with you? How much longer must I endure you? Bring him to me."

Mark 16:14

Then he appeared to the eleven themselves, while they were eating, and he rebuked them for their unbelief and hardness of heart, because they did not believe those who had seen him resurrected.

Hebrews 5:11-12

On this topic we have much to say and it is difficult to explain, since you have become sluggish in hearing.

Treasury of Scripture Knowledge

Summary

Luke 24:25

Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken:

O fools

Hebrews 5:11

General references

Matthew 26:54

Mark 7:18

Luke 18:34

Bible References

O fools

He said to them, "Are you so foolish? Don't you understand that whatever goes into a person from outside cannot defile him?

When he learned of this, Jesus said to them, "Why are you arguing about having no bread? Do you still not see or understand? Have your hearts been hardened?

He answered them, "You unbelieving generation! How much longer must I be with you? How much longer must I endure you? Bring him to me."

Then he appeared to the eleven themselves, while they were eating, and he rebuked them for their unbelief and hardness of heart, because they did not believe those who had seen him resurrected.

On this topic we have much to say and it is difficult to explain, since you have become sluggish in hearing.

General references

How then would the scriptures that say it must happen this way be fulfilled?"

He said to them, "Are you so foolish? Don't you understand that whatever goes into a person from outside cannot defile him?

But the twelve understood none of these things. This saying was hidden from them, and they did not grasp what Jesus meant.