1.  Jesus surprises a Pharisee by not participating in the ritual washing required by the rabbis before a meal.  He used this as an occasion to correct their false view of spirituality and to address the hypocrisy, greed, and self-indulgence of the Pharisees.

2.  To the Pharisees (and all religionists/legalists) religion is a matter of external form and ritual rather than of the heart (the inner person).

3.  It is ludicrous to cleanse the outside and not the inside.  Washing the hands (the outside) did not make the heart pure (the inside).

4.  The heart is where sin proceeds from (Mark 7:17-23; Matthew 15:15-20) and is not touched by ritual handwashing.  True spirituality begins with the heart (and works it way out to the actions) not the hands.  The heart must be guarded (Proverbs 4:23) for it is the genesis of our actions.  The heart is only touched by the Spirit of God through the Word of God.