Matthew 16:12
Then they understood, that He did not bid them beware of the leaven of bread, but of the doctrine of the pharisees and of the sadducees.
Luke 12:1
In the mean time great multitudes of people being gathered together about Him, so that they trode upon one another, He began to say to his disciples, Beware of the leaven of the pharisees, which is hypocrisy: for there is nothing concealed,
Acts 12:3
And seeing that it was pleasing to the Jews, he proceeded to apprehend Peter also, (in the days of unleavened bread:)
1 Corinthians 5:7-8
Purge out therefore the old leaven, that ye may be a new mass, without leaven. For our paschal lamb, even Christ, was slain for us.
Galatians 5:12
I wish they were even cut off from your communion, that make such disturbance amongst you.