6 Jesus said to them, "Watch and beware of the leaven of the Pharisees and Sadducees." 7 And they began discussing it among themselves, saying, "We brought no bread." 8 But Jesus, aware of this, said, "O you of little faith, why are you discussing among yourselves the fact that you have no bread? 9 Do you not yet perceive? Do you not remember the five loaves for the five thousand, and how many baskets you gathered? 10 Or the seven loaves for the four thousand, and how many baskets you gathered? 11 How is it that you fail to understand that I did not speak about bread? Beware of the leaven of the Pharisees and Sadducees." 12 Then they understood that he did not tell them to beware of the leaven of bread, but of the teaching of the Pharisees and Sadducees.
Matthew Henry's Commentary on Matthew 16:6-12
Commentary on Matthew 16:5-12
(Read Matthew 16:5-12)
Christ speaks of spiritual things under a similitude, and the disciples misunderstand him of carnal things. He took it ill that they should think him as thoughtful about bread as they were; that they should be so little acquainted with his way of preaching. Then understood they what he meant. Christ teaches by the Spirit of wisdom in the heart, opening the understanding to the Spirit of revelation in the word.