Mark 8:21

And He said unto them, How is it that ye do not understand?

Jesus had been busy with His thoughts, but His attention was now directed to His disciples by their whispering and consulting. And, without inquiring, by virtue of His omniscience, He knew the matter of their dispute and their conclusion. That was a worse blow than the enmity of the Pharisees. He gives utterance to a sharp reprimand in the form of a bitter complaint: Why are you consulting together about loaves which you have not? Not yet do you know or understand? Yet have you a heart that is calloused? Having eyes you see not, and having ears you hear not, and do not remember? It was lack of faith, lack of trust in Him, which was evident in the case of the disciples, as if there were nothing higher to be thought of than bread. They were almost on a level with the Jews to whom the Lord had applied the word of Isaiah concerning the hardness of their hearts. But, after all, it was only weakness, and not malice, in their case. And so the Lord uses a gentler tone in reminding them of the two great miracles of feeding which they had witnessed. He comes to their assistance by catechizing them on these exhibitions of divine power, to see whether they had taken proper note of all incidents. This they had remembered and answered correctly. And now He again urges them to consider the matter once more, very carefully, and see whether they could not reach the right conclusion. And this time they understood what He had referred to and what He wanted to teach, Matthew 16:12.