Matthew 13:51
"Do you understand all these stories?" They answered Him, "Yes."
Matthew 15:16-17
And He said, "Are you too, even yet, without understanding?
Matthew 16:11
How is it that you do not understand that I did not speak to you about bread, when I said, keep on guarding yourselves against the yeast of the Pharisees and the Sadducees?"
Mark 4:13
Then He said to them: "If you do not understand this story, how, indeed, can you understand any of my stories?
Luke 9:45
But they remained ignorant of what this meant; indeed, it had been hidden from them, so that they did not grasp it, and they were afraid to ask Him about this statement.
Acts 8:30
Then Philip ran up and listened to him reading the prophet Isaiah, and he asked, "Do you understand what you are reading?"