Luke 24:25

And He said to them, “O foolish men and slow of heart to believe in all that the prophets have spoken!

Mark 7:18

And He *said to them, “Are you so lacking in understanding also? Do you not understand that whatever goes into the man from outside cannot defile him,

Mark 8:17-18

And Jesus, aware of this, *said to them, “Why do you discuss the fact that you have no bread? Do you not yet see or understand? Do you have a hardened heart?

Mark 9:19

And He *answered them and *said, “O unbelieving generation, how long shall I be with you? How long shall I put up with you? Bring him to Me!”

Mark 16:14

Afterward He appeared to the eleven themselves as they were reclining at the table; and He reproached them for their unbelief and hardness of heart, because they had not believed those who had seen Him after He had risen.

Hebrews 5:11-12

Concerning him we have much to say, and it is hard to explain, since you have become dull of hearing.

Treasury of Scripture Knowledge

Summary

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

General references

Bible References

O fools

Mark 7:18
And He *said to them, “Are you so lacking in understanding also? Do you not understand that whatever goes into the man from outside cannot defile him,
Mark 8:17
And Jesus, aware of this, *said to them, “Why do you discuss the fact that you have no bread? Do you not yet see or understand? Do you have a hardened heart?
Mark 9:19
And He *answered them and *said, “O unbelieving generation, how long shall I be with you? How long shall I put up with you? Bring him to Me!”
Mark 16:14
Afterward He appeared to the eleven themselves as they were reclining at the table; and He reproached them for their unbelief and hardness of heart, because they had not believed those who had seen Him after He had risen.
Hebrews 5:11
Concerning him we have much to say, and it is hard to explain, since you have become dull of hearing.

General references

Matthew 26:54
How then will the Scriptures be fulfilled, which say that it must happen this way?”
Mark 7:18
And He *said to them, “Are you so lacking in understanding also? Do you not understand that whatever goes into the man from outside cannot defile him,
Luke 18:34
But the disciples understood none of these things, and the meaning of this statement was hidden from them, and they did not comprehend the things that were said.