Matthew 16:12
Then they realized that he had not told them to beware of the leaven, but of the teaching of the Pharisees and Sadducees.
Luke 12:1
Meanwhile when myriads of the multitudes were thronging around him so that they trod one upon another, he began to say to his disciples, first of all. "Beware of the leaven of the Pharisee, which is hypocrisy.
Acts 12:3
And when he saw that it pleased the Jews, he proceeded to seize Peter also. (This was during the days of unleavened bread.)
1 Corinthians 5:7-8
Then get rid of the old leaven, so that you may be like a new lump, as you are now unleavened. For our Paschal Lamb has already been sacrificed, Christ himself.
Galatians 5:12
Would to God that those who are trying to unsettle you would even have themselves mutilated.