When the disciples reached the other side, they had forgotten to bring any bread. Jesus said to them, “Watch and beware of the leaven of the Pharisees and Sadducees.” And they began discussing it among themselves, saying, “We brought no bread.” But Jesus, aware of this, said, “O you of little faith, why are you discussing among yourselves the fact that you have no bread? Do you not yet perceive? Do you not remember the five loaves for the five thousand, and how many baskets you gathered? Or the seven loaves for the four thousand, and how many baskets you gathered? How is it that you fail to understand that I did not speak about bread? 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 teaching of the Pharisees and Sadducees.
I can really relate to the disciples. So often my troubles seem so large. So often the minutiae of forgotten bread obscures my thinking and makes me forget about the miracles of His provision - He always meets my needs. When I find myself worrying about forgotten bread I am reminded about how the Lord instructs me to trust Him with my heart and not lean on my own understanding. Worry is of the head but trust is a heart thing.
Jesus calls the teaching of the religious leaders leaven because teaching and teachers influence us in a major fashion. I sat under the teaching of a fundamentalist pastor for 16 years. His teaching influenced me to embrace the scriptures in a very literal and legalistic fashion. His teaching fed a dark part of me. Such is why Jesus told his disciples to be on the alert when the Pharisees and Sadducees taught.
Lord, help me to discern when I am being influenced by false teaching.