'Unable' in the Bible

“You have heard that it was said to the men of old, ‘You shall not murder,’ and ‘Whoever murders shall be guilty before the court.’

But I say to you that everyone who continues to be angry with his brother or harbors malice against him shall be guilty before the court; and whoever speaks [contemptuously and insultingly] to his brother, ‘Raca (You empty-headed idiot)!’ shall be guilty before the supreme court (Sanhedrin); and whoever says, ‘You fool!’ shall be in danger of the fiery hell.

And He said, “Are you still so dull [and unable to put things together]?

And He came to the disciples and found them sleeping, and said to Peter, “So, you men could not stay awake and keep watch with Me for one hour?