“He summoned the multitude, and said to them, Hear and understand. That which enters into the mouth doesn’t defile the man, but that which proceeds out of the mouth, this defiles a man” – Matthew 15:10-11
Jesus told us what really defiles a person. In the Old Testament defiled meant you were spiritually unclean or impure. It rendered you unfit for divine purposes, as in a priest could not serve while he was defiled, or a “regular” person would not be able to go to the temple, until you were cleansed.
To the Jewish people of Jesus’s day if you ate without washing your hands, or ate certain foods, touched a dead person, touched someone with leprosy, or touched bodily fluids you would be defiled and would need to go through a cleansing ritual.
Jesus flips the narrative on what the law said, and says those things don’t make you defiled. But how could Jesus do that? How could he change the law given by God? Eating with unwashed hands was not a biblical law, but a tradition of the fathers . He could change the law because He was the one who made the laws. He was fully God in His eternal spirit and divine nature.
Jesus makes it clear that the development is a matter of the heart, not the stomach. In Mark 7:18 19 Jesus told His disciples, after they were away from the multitudes, “Are you also without understanding? Don’t you perceive that whatever goes into the man from outside can’t defile him, because it doesn’t go into his heart, but into his stomach, then into the latrine, that purifying all foods?”
The Old Testament says we should eat certain things. But Jesus in the New Testament Jesus declared all foods clean.
Jesus turned certain parts of the Old Testament on its head. Not moral laws but ceremonial laws.
We become defiled when we in our hearts and minds give space for sinful thoughts, instead of shutting them down.
From Pity to Praise 