Jesus made this statement while speaking to a crowd that was very familiar with the norms that the Old Testament and the rabbinical teaching had prescribed in order to approach the sacred area of the temple. It was a complex ritual of ablutions and the washing of objects which Mark's Gospel had described (Mk. 7:3-4). That exterior purification was meant to be the expression of an interior, spiritual purity, but in reality, the true meaning of those rituals had been forgotten, and the focus was on a scrupulous and formal observance of countless rules.

«Nothing that enters one from outside can defile that person; but the things that come out from within are what defile.»

Even though this affirmation was perfectly compatible with Jewish law, the position which Jesus took was quite courageous because it went against the current. He was continuing along the great tradition of the prophets, who had always called the people to an authentic cult, that is, practiced with all their heart and soul, and not only exteriorly, concerned solely with avoiding physical contact with foods and objects declared to be impure.
Here then, as in all his preaching and behavior, Jesus does not want to abolish the Law, but to bring it to fulfillment (cf. Mt. 5:27), that is, to bring it back to its profound meaning and goal, which is that of drawing human beings closer to God.

«Nothing that enters one from outside can defile that person; but the things that come out from within are what defile.»

“…the things that come out from within are what defile.”
This second part of Jesus words deals with that which really makes us unclean: we are not contaminated by what enters in us, but by what comes out of us. From within, from people's hearts, come evil thoughts and intentions, which are the cause of: “unchastity, theft, murder, adultery, greed, malice, deceit, licentiousness, envy, blasphemy, arrogance, folly (Mk. 7:21-22).
Jesus views creation as good and knows full well that the human person was created in God's image and likeness. He also knows human nature and its tendency towards evil; thus he demands that we convert.
His moral severity emerges clearly from the words we are considering. He wants to create in us a pure and sincere heart which, like a clear spring, will give rise to good thoughts and blameless actions.

«Nothing that enters one from outside can defile that person; but the things that come out from within are what defile.»

How then can we live these words?
If it is not the food and the other material things that come to us from our surroundings that make us unclean and separate us from friendship with God, but rather our own self – our own heart, and decisions – then it is obvious that Jesus wants us to reflect on the true motives behind our actions and behavior.
And we know that for Jesus, only love can purify everything we do.
One who loves, does not sin or kill, or speak ill of others, or steal or betray…
So then, let us be guided twenty-four hours a day by love: love for God and for our neighbors. We will then be true Christians.

Chiara Lubich