Gotta admire those Pharisees, they know how to keep their eye on the money. No matter how often they wash, their hands are dirty with money that should be going to the aged and infirm. I don't want to make a social issue out of this, but it is clear that Jesus wants the old and infirm well provided-for in dignity and love. The Pharisees were more interested in building their own retirement fund, and they had a clever investment plan: get the fish to "give money to God" instead of supporting their parents. Hey, what could be more important than giving to God, right? No doubt there are well-advertised perks and advantages in this world and the next that accrue to such generous givers. And Mom and Dad? No doubt God will take care of them, too - just have faith.
The more I read Matthew, the more convinced I am that Jesus (like Isaiah and Amos and other prophets before him) were telling Israel that God is heartily sick of religion without love informed by God's law. The awful corruptions coming out of the heart of man are hidden in false piety. Adultery: 'Let me pray with you, sister." Murder: "Slay the infidels." Theft: "It's okay to take the Indians' land because they are heathen Canaanites and we are the Israel of God." The heart of man is desperately wicked and self-deceived. Lord give us grace to choose.
P.S. notice that Jesus appears surprised, again, by the faith of a Gentile seeking a miracle. How refreshing it must be to him, and how challenging to the decadent children of Israel watching the exchange. God is pleased by faith, not lineage.