Matthew 16:5-12 NASB
And the disciples came to the other side of the sea, but they had forgotten to bring any bread. And Jesus said to them, “Watch out and beware of the leaven of the Pharisees and Sadducees.” They began to discuss this among themselves, saying, “He said that because we did not bring any bread.” But Jesus, aware of this, said, “You men of little faith, why do you discuss among yourselves that you have no bread? Do you not yet understand or remember the five loaves of the five thousand, and how many baskets full you picked up? Or the seven loaves of the four thousand, and how many large baskets full you picked up? How is it that you do not understand that I did not speak to you concerning bread? But beware of the leaven of the Pharisees and Sadducees.” Then they understood that He did not say to beware of the leaven of bread, but of the teaching of the Pharisees and Sadducees.
NASB: New American Standard Bible