Church Fathers on Matthew 23:11

The Lord bad charged the Scribes and Pharisees with harshness and neglect; He now brings forward their vain-glory, which made them depart from God.

Every substance breeds in itself that which destroys it, as wood the worm, and garments the moth so the Devil strives to corrupt the ministry of the Priests, who are ordained for the edification of holiness, endeavouring that this good, while it is done to be seen of men, should be turned into evil. Take away this fault from the clergy, and you will have no further labour in their reform, for of this it comes that a clergyman who has sinned can hardly perform penance.

And their works likewise they do to be seen of men, using outward circumcision, taking away actual leaven out of their houses, and doing such like things. But Christ’s disciples fulfil the Law in things secret, being Jews inwardly, as the Apostle speaks. [marg. note: Rom 2:29]