Luke 11:39

Now mark that our bodies are signified by the mention of earthly and fragile things, which when let fall a short distance are broken to pieces, and those things which the mind meditates within, it easily expresses through the senses and actions of the body, just as those things which the cup contains within make a glitter without. Hence also hereafter, by the word cup doubtless the passion of the body is spoken of. You perceive then, that not the outside of the cup and platter defiles us, but the inner parts. For he said, But your inward part is full of ravening and wickedness.

Now our Lord might also have used other words to admonish the foolish Pharisee, but he seizes the opportunity and framed his reproof from the things that were ready before him. At the hour, namely, of meals He takes for His example the cup and the platter, pointing out that it became the sincere servants of God to be washed and clean, not only from bodily impurity, but also from that which lies concealed within the power of the soul, just as any of the vessels which are used for the table ought to be free from all inward defilement.

(Serm. 106.) For every day before dinner the Pharisees washed themselves with water, as if a daily washing could be a cleansing of the heart. But the Pharisee thought within himself, yet did not give utterance to a word; nevertheless, He heard who perceived the secrets of the heart. Hence it follows, And the Lord said unto him, Now do ye Pharisees make clean the outside of the cup and the platter; but your inward part is full of ravening and wickedness.