Galatians 5:9
A little leaven leavens all the dough.
1 Corinthians 15:33
Do not be deceived. 'Good character is marred by evil company.'
Matthew 16:6-12
Presently Jesus said to them: "Take care and be on your guard against the leaven of the Pharisees and Sadducees."
Matthew 23:33
You serpents and brood of vipers! How can you escape being sentenced to the Pit?
Mark 8:15
So Jesus gave them this warning. "Take care," he said, "beware of the leaven of the Pharisees and the leaven of Herod."
Luke 12:1
Meanwhile the people had gathered in thousands, so that they trod upon one another, when Jesus, addressing himself to his disciples, began by saying to them: "Be on your guard against the leaven--that is, the hypocrisy--of the Pharisees.
Luke 13:21
It is like some yeast which a woman took and covered in three pecks of flour, until the whole had risen."
1 Corinthians 5:6-7
Your boasting is unseemly. Do not you know that even a little leaven leavens all the dough?
2 Timothy 2:17
and their teaching will spread like a cancer. Hymenaeus and Philetus are instances of this.