'Leaven' in the Bible
Another story he gave to them: The kingdom of heaven is like leaven, which a woman took, and put in three measures of meal, till it was all leavened.
And Jesus said to them, Take care to have nothing to do with the leaven of the Pharisees and Sadducees.
How is it that you do not see that I was not talking to you about bread, but about keeping away from the leaven of the Pharisees and Sadducees?
Then they saw that it was not the leaven of bread which he had in mind, but the teaching of the Pharisees and Sadducees.
And he said to them, Take care to be on the watch against the leaven of the Pharisees and the leaven of Herod.
At that time, when thousands of the people had come together, in such numbers that they were crushing one another, he said first to his disciples, Have nothing to do with the leaven of the Pharisees, which is deceit.
It is like leaven, which a woman put into three measures of meal, and it was all leavened.
This pride of yours is not good. Do you not see that a little leaven makes a change in all the mass?
Take away, then, the old leaven, so that you may be a new mass, even as you are without leaven. For Christ has been put to death as our Passover.
Let us then keep the feast, not with old leaven, and not with the leaven of evil thoughts and acts, but with the unleavened bread of true thoughts and right feelings.