What is yeast or leaven a picture of?

Here's another point: yeast represents sin. As the Israelites were to sweep out their houses to remove any possible remaining yeast, when we accept Christ, God sweeps the sin out our hearts. We are no longer infected with sin; we are made pure, as with the bread without yeast.

Remember, also, Jesus is bread of life, pure and without sin (yeast)

<3

(Thank you, google!)