64 Here καί (kai) has been translated as “so” to indicate the implied result of the disciples’ inability to believe in Jesus’ resurrection.
65 Grk “O,” an interjection used both in address and emotion ( 1).
66 The word “people” is not in the Greek text, but is supplied to complete the interjection.
67 The rebuke is for failure to believe the promise of scripture, a theme that will appear in vv. 43–47 as well.
68 On the syntax of this infinitival construction, see ἐπί 6.b.

In other versions

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

He said to them, “How foolish you are, and how slow to believe all that the prophets have spoken!

He said to them, “How foolish you are, and how slow to believe all that the prophets have spoken!

Then Jesus said to them, “You foolish people! You find it so hard to believe all that the prophets wrote in the Scriptures.

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

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

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