“Jesus often uses current situations to teach us eternal truths. He hears them talking about the bread and He uses that to try to warn them about dangerous influences that will try to worm their way into a disciple’s heart. He uses a physical situation to teach them about living the spiritual life.
Leaven, by the way, is not exactly the same as yeast. In fact, yeast was rare in antiquity. Leaven is a synonym for corruption. Jesus is saying here, “Watch out that these influences don’t corrupt your life.” First, the leaven of the Pharisees. In Luke, Jesus says the leaven of the Pharisees is hypocrisy. They claimed to be righteous while in reality dishonoring God. In Matthew, the leaven of the Pharisees is their false teaching. The idea that rules and rituals make you right with God. Legalism.
What was Herod’s leaven? Well, Herod was all about self. He was all about license and wealth and power and pleasure. And around him there was a group called the Herodians. These were Jews who saw Herod’s rule as a way to get political power.
So, you have legalism on one side and license on the other. You have the corrupting influence of self-righteousness and the corrupting influence of self-indulgence. And Jesus says, “Hey, watch out for this stuff. Because a little bit of either will spread through your life and change the whole composition of who you are.”
These are viruses that really can infect us. You get to Acts and you see that in the church there is a whole group who call themselves “The party of the Pharisees.” When we look at the church in Corinth, we see they’re deep into license and self-indulgence – the leaven of Herod. So we need to take this warning to heart.”
