Part 1: Getting God Wrong
Jesus points out that we can have a wrong perception of God and what he wants when we are bound by rigid regulations from Matthew 12:1-8.  
Part 2: The Jesus We Never Knew
Jesus points out that we can lose sight of true spirituality when we place our religious systems over the real needs of people from Matthew 12:9-21.  
Part 3: Getting Serious
Jesus addresses the ignorance that many have concerning spiritual realities and calls his listeners follow him from Matthew 12:22-30.  
Part 4: The Inward Reality
Jesus stresses that focusing on the outward appearance without an inward change brings condemnation from Matthew 12:38-50.