Matthew 16:6, 11-12

“Be careful,” Jesus said to them. “Be on your guard against the yeast of the Pharisees and Sadducees.”

How is it you don’t understand that I was not talking to you about bread? But be on your guard against the yeast of the Pharisees and Sadducees.” Then they understood that he was not telling them to guard against the yeast used in bread, but against the teaching of the Pharisees and Sadducees.