All these evil things come out from within and defile the person.”
This concluding statement summarizes the whole teaching. A person is defiled by the evil that comes out from within him. Thus, the center of the problem is the heart. Here lies the necessity of the Gospel. If defilement comes from within, then a person needs not only outward correction, but inward renewal. He does not need merely better discipline, but a new heart. This teaching of Christ directly prepares a person to understand why the new birth, repentance, and the grace of God are necessary. Whoever hears this and understands it rightly stops trusting in outward righteousness and begins to cry out for inward cleansing.