Galatians 5:9
A little leaven is leavening the whole lump.
1 Corinthians 15:33
Do not deceive yourselves. Evil companions ruin good morals.
Matthew 16:6-12
Presently Jesus said to them, "Take heed and beware of the leaven of the Pharisees."
Matthew 23:33
"You serpents! You vipers brood! How shall you escape the judgment of hell?
Mark 8:15
So he gave them this warning. "Look out! Be on the watch against the leaven of the Pharisees, and the leaven of Herod."
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.
Luke 13:21
"It is like leaven which a took and hid in three measures of flour until the whole was leavened."
1 Corinthians 5:6-7
Your glorying is not good. Do you not know that even a little leaven leavens all the lump?
2 Timothy 2:17
and their teaching will spread like a gangrene.