But Jesus, knowing their thoughts, said, “Why do you think evil in your hearts?
4. And when Jesus saw their thoughts He now gives a proof of his Divinity in bringing to light their secret thoughts: for who knoweth the things of a man but the spirit of man which is in him? (1 Corinthians 2:11.) And so Mark adds, that Jesus knew by his Spirit: which means, that what was concealed in their hearts could not be perceived...
The first words of this chapter oblige us to look back to the close of that which precedes it, where we find the Gadarenes so resenting the loss of their swine, that they were disgusted with Christ's company, and besought him to depart out of their coasts. Now here it follows, He entered into a ship, and passed over.
Commenting on Matthew 9:1-8
And Jesus knowing their thoughts,.... Which was a clear evidence, and full demonstration of his deity; for none knows the thoughts of the heart but God; and since he knew the thoughts of men's hearts, it could be no blasphemy in him to take that to himself which belonged to God, even to forgive sins.