The Leaven of the Pharisees
The Pharisees and Sadducees were not satisfied with the overwhelming evidence that Jesus was the Messiah and so they sought from Him a sign that they could deny was a legitimate reason to believe in Him. Jesus would not give them what they asked. Their own teaching from their hearts was like leaven that impacted the whole loaf. They were wicked men not to be followed, but there is much to learn from their poor example. We must treasure Christ and trust Him based on what He has already promised and already given us through our salvation.