25 Then he said to them, O fools, and slow of heart to believe all that the prophets have spoken!
Luke 24:25 Cross References - Webster
Mark 7:18
18 And he saith to them, Are ye so void of understanding also? Do ye not perceive, that whatever thing from without entereth into the man, it cannot defile him.
Mark 8:17-18
Mark 9:19
19 He answered him, and saith, O faithless generation, how long shall I be with you, how long shall I suffer you? bring him to me.
Mark 16:14
14 Afterward he appeared to the eleven, as they sat at table, and upbraided them with their unbelief, and hardness of heart, because they believed not them who had seen him after he was risen.
Hebrews 5:11-12
11 Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing.
12 For when for the time ye ought to be teachers, ye have need of one to teach you again which are the first principles of the oracles of God; and are become such as have need of milk, and not of strong food.