Scripture/Text: Matthew 16:1-12; This week's message from Matthew 16 focused on two big ideas. First, beware of bad teaching. Second, behold the sign of Jonah. Bad teaching is metaphorically described as leaven. It is subtle but powerfully works through entire life or community. The bad teaching Jesus is referring to in his day is the bad teaching of two very different Jewish groups, the Pharisees and the Sadducees. The principles of bad teaching that we should learn from them for our own day include: 1) Any teaching that makes little of Jesus; 2) Teaching that is too liberal or too conservative; and 3) Teaching that is hypocritical, that is, teaching that focuses on the external behavior and not heart transformation.