John Calvin Commentary Luke 11:39

"And the Lord said unto him, Now ye the Pharisees cleanse the outside of the cup and of the platter; but your inward part is full of extortion and wickedness." — Luke 11:39 (ASV)

Now you Pharisees. Christ does not here charge the Pharisees, as in Matthew (Matthew 15:1–20) and Mark (Mark 12:2–13), with serving God in an improper manner by human inventions and breaking the law of God for the sake of their traditions; but merely glances at their hypocrisy, in having no desire for purity except before the eyes of men, as if they did not have to deal with God. This reproof applies to all hypocrites, even to those who believe that righteousness consists in ceremonies appointed by God. Christ includes more than if he had said that it is in vain to serve God by the commandments of men (Mark 7:7); for he generally condemns the error of worshipping God by ceremonies and not spiritually, by faith and a pure affection of the heart.

On this point the prophets had always contended earnestly with the Jews; but, as human minds are strongly inclined to hypocrisy, they proudly and obstinately adhered to the conviction that God is pleased with external worship, even when it is not accompanied by faith. In the time of Christ, however, they had sunk to such a depth of folly that they made religion consist entirely in absolute trifles.

Accordingly, he directs his accusation against the Pharisees, for being extremely careful to wash cups, and cherishing within their hearts the most abominable filth of cruelty and wickedness. He charges them with folly on this ground: that God, who created that which is within the man, his soul, as truly as the body, cannot be satisfied with a mere external appearance.

The chief reason why people are deceived is that they do not consider that they have to deal with God, or they transform Him according to the vanity of their senses, as if there were no difference between Him and a mortal man.