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.
Also the Lord here points out the cause why they could not believe in Christ, because nearly all they did was in order to be seen of men; for he whose desire is for earthly glory from men, cannot believe on Christ who preaches things heavenly.
I have read one who interprets this place thus. “In Moses’ seat,” that is, in the rank and degree instituted by Moses, the Scribes and Pharisees are seated unworthily, forasmuch as they preached to others the Law which foretold Christ’s coming, but themselves did not receive Him when come. For this cause He exhorts the people to hear the Law which they preached, that is, to believe in Christ who was preached by the Law, but not to follow the Scribes and Pharisees in their disbelief of Him. And He shews the reason why they preached the coming of Christ out of the Law, yet did not believe on Him; namely, because they did not preach that Christ should come through any desire of His coming, but that they might be seen by men to be doctors of the Law.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).