Bible Verses about Leaven as Corrupt Doctrine
Then Jesus said to them, "Take heed and beware of the leaven of the Pharisees and the Sadducees."
How is it you do not understand that I did not speak to you concerning bread?—but to beware of the leaven of the Pharisees and Sadducees." Then they understood that He did not tell them to beware of the leaven of bread, but of the doctrine of the Pharisees and Sadducees.
1 Corinthians 5:6-8
Your glorying is not good. Do you not know that a little leaven leavens the whole lump? Therefore purge out the old leaven, that you may be a new lump, since you truly are unleavened. For indeed Christ, our Passover, was sacrificed for us. Therefore let us keep the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth.
"No grain offering which you bring to the LORD shall be made with leaven, for you shall burn no leaven nor any honey in any offering to the LORD made by fire.
Then He charged them, saying, 'Take heed, beware of the leaven of the Pharisees and the leaven of Herod.'
In the meantime, when an innumerable multitude of people had gathered together, so 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.
1 John 4:20-21
If someone says, "I love God," and hates his brother, he is a liar; for he who does not love his brother whom he has seen, how can he love God whom he has not seen? And this commandment we have from Him: that he who loves God must love his brother also.
Another parable He spoke to them: "The kingdom of heaven is like leaven, which a woman took and hid in three measures of meal till it was all leavened."
A little leaven leavens the whole lump.