Matthew 16:1, 6, 12

The Pharisees and Sadducees came to Jesus, wanting to trick him. So they asked him to show them a miracle from God.

Jesus said to them, “Be careful! Beware of the yeast of the Pharisees and the Sadducees.”

Then the followers understood that Jesus was not telling them to beware of the yeast used in bread but to beware of the teaching of the Pharisees and the Sadducees.