Matthew 16:1, 6, 12

And the Pharisees and Sadducees came, and trying him asked him to show them a sign from heaven.

And Jesus said unto them, Take heed and beware of the leaven of the Pharisees and Sadducees.

Then understood they that he bade them not beware of the leaven of bread, but of the teaching of the Pharisees and Sadducees.