14 Then he summoned the crowd again and said to them, “Listen to me, all of you, and understand: 15 there is nothing outside a person that can make it ordinary by going in, but the things that come out are what make something ordinary.” 16 17 When he had left the crowd and came into the house, his disciples asked him about the parable. 18 He said to them, “Then do you also fail to understand? Do you not see that whatever goes into a person from outside cannot make him ordinary, 19 since it enters, not the heart but the stomach, and goes out into the sewer?” (By this he declared all foods clean.) 20 And he said, “It is what comes out of a person that makes someone ordinary. 21 For it is from within, from the human heart, that evil thoughts come: sexual sin, theft, murder, 22 adultery, greed, wickedness, deceit, immorality, envy, slander, pride, folly. 23 All these evil things come from within, and they make a person ordinary.”
I recently sent my laptop in to be repaired. I got it back all shiny and new looking, and could not wait to get it home, turn it on, and be amazed. I was greatly disappointed, because it had not been repaired at all. It had just been cleaned. There was something defective inside it, so no matter how good it looked, it was useless for the purpose intended by its creators.
The problem that the Pharisees and scribes had brought up was spiritual defilement. The theology they believed asserted that human beings had the capacity to be holy, and thus useful for God and his purposes, but that something like eating without ceremonial washing of the hands would render humans defiled, fit for only ordinary things.
Jesus comes along and challenges that theology. He agreed that spiritual defilement is a problem, but he asserted that it was not caused by something on the outside – like something you eat. No, spiritual defilement begins in the human heart, which “is deceitful above all things, And desperately wicked.” If there is any hope of us ever rising above this condition, the cure must begin there.
LORD, repair our defects on the inside, so that we might be unique and useful for you and your kingdom.
 Jeremiah 17:9.