Mark 7:18

He said to them, "Are you also as lacking in understanding [as the others]? Do you not understand that whatever enters a person's body from the outside cannot [spiritually] corrupt him?

Matthew 15:16-17

And He replied, "Are you still unable to understand?

Matthew 16:11

How is it that you do not understand that I was not speaking to you about [physical] bread? But [rather I meant] watch out for the yeast [i.e., the influence] of the Pharisees and Sadducees."

Mark 4:13

And Jesus continued to speak to them, "Do you not know what this parable means? Then how can you understand any of the other parables?

Luke 24:25

Then Jesus said to them, "You foolish men! How slow your minds are to believe everything the prophets have spoken [in their writings]!

John 3:10

Jesus answered him, "Are you a teacher of the Israelites and [yet] you do not understand these things?

1 Corinthians 3:2

For I fed you with milk, not with solid food [i.e., with basic fundamentals instead of more advanced teaching. See Heb. 5:12-13] because you were not able to absorb it,

Hebrews 5:11

[Now] we have many things to say about Melchizedek, but because of your slowness to grasp things, they are hard to explain.

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