Matthew 15:7-9 7 "You hypocrites (ὑποκριταί), rightly did Isaiah prophesy of you: 8 'THIS PEOPLE HONORS ME WITH THEIR LIPS, BUT THEIR HEART IS FAR AWAY FROM ME. 9 'BUT IN VAIN DO THEY WORSHIP ME, TEACHING AS DOCTRINES THE PRECEPTS OF MEN.'"
JC Ryle puts it so well:
I do not deny that there are many hypocrites in religion. There always were, and there always will be, as long as the world stands. As long as there is good gold and silver coin in the realm, so long there will be forging, coining, and counterfeit money. The very existence of bad coins is an indirect proof that there is something which it is worth while to imitate, and that there is such a thing as good current money in circulation. It is just the same with Christianity! The very fact that there are many false professors in the churches is an indirect proof that there are such people as true-hearted and sound believers. It is one of Satan’s favorite devices, in order to bring discredit on Christianity, to persuade some unhappy people to profess what they do not really believe. He tries to damage the cause of our Lord Jesus Christ in the world by sending out wolves in sheep’s clothing, and by raising up men and women who talk the language of Canaan, and wear the coat of God’s children, while they are inwardly rotten at heart.