Jesus did not criticize this Pharisee and his religious brethren for washing their hands before eating or for observing ritual purification beyond what the law required. He used His host"s objection as an occasion to point out the hypocrisy involved in Pharisaic teaching and practice. The Pharisees typically neglected more important things while stressing the necessity of much less important things (cf. Luke 6:27-36; Luke 10:25-37). By washing ceremonially they were only doing half of what God expected of them. They needed to purify themselves internally as well as externally. To wash the outside of a person and not cleanse the inside is as foolish as only washing the outside of a bowl without washing the inside. [source][source][source]
"Did not he (the potter or God) who made the outside also make the inside (and therefore you must cleanse both)?" [1][source]
"The way to clean up a dirty vocabulary is not to brush your teeth but to cleanse your heart." [2][source]