Matthew 16:6

16:6 “Watch out,” Jesus said to them, “beware of the yeast of the Pharisees and Sadducees.”

Matthew 16:11-12

16:11 How could you not understand that I was not speaking to you about bread? But beware of the yeast of the Pharisees and Sadducees!” 16:12 Then they understood that he had not told them to be on guard against the yeast in bread, but against the teaching of the Pharisees and Sadducees.