Matthew 15:10 And he called the people to him and said to them, “Hear and understand: [11] it is not what goes into the mouth that defiles a person, but what comes out of the mouth; this defiles a person.” [12] Then the disciples came and said to him, “Do you know that the Pharisees were offended when they heard this saying?” [13] He answered, “Every plant that my heavenly Father has not planted will be rooted up. [14] Let them alone; they are blind guides. And if the blind lead the blind, both will fall into a pit.” [15] But Peter said to him, “Explain the parable to us.” [16] And he said, “Are you also still without understanding? [17] Do you not see that whatever goes into the mouth passes into the stomach and is expelled? [18] But what comes out of the mouth proceeds from the heart, and this defiles a person. [19] For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander. [20] These are what defile a person. But to eat with unwashed hands does not defile anyone.”

Our greatest problem is not what is around us, but what is within us. 
      I. Defilement does not come from outside us (vv. 10–11) 
     II. Blind religion cannot cure what is inside us (vv. 12–14)
   III. Sin flows from the heart within us (vv. 15–20)
   IV. We need God to give us a new heart