What the Bible says about Leaven of Corrupt Doctrine
(From Forerunner Commentary)
The crux—the pivot point—of the chiasm is in the fourth and fifth parables, those of the Leaven and the Hidden Treasure (Matthew 13:33, 44). They both involve something hidden that affects the realm of God's dominion either negatively (the leaven of corrupt doctrine) or positively (the hidden treasure of God-given faith). The fifth parable's hidden treasure solves the problem of the leaven in the fourth parable. The nation's overall problem was a lack of faith, produced by a twisted, demonic belief system that left many citizens in direct opposition to their King and Savior. The solution—the work of God (John 6:29)—was His intervention in the lives of some so they could truly believe.
David C. Grabbe
God's Kingdom in the Parables (Part Four): The Pearl, the Dragnet, and the Householder