Matthew 16:12
Then they understood that he did not tell them to beware of the leaven of bread, but of the teaching of the Pharisees and Sadducees.
Luke 12:1
In the meantime, when so many thousands of the multitude had gathered together that they trampled one another, he began to say to his disciples first of all, "Beware of the leaven of the Pharisees, which is hypocrisy.
Acts 12:3
When he saw that it pleased the Jews, he proceeded to arrest Peter also. This was during the days of Unleavened Bread.
1 Corinthians 5:7-8
Cleanse out the old leaven that you may be a new lump, as you really are unleavened. For Christ, our Passover lamb, has been sacrificed.
Galatians 5:12
I wish that those who are troubling you would mutilate themselves!