Quotes about hypocrisy from throughout Christian History.
It is better for a man to be silent and be [a Christian], than to talk and not be one. It is good to teach, if he who speaks also acts. … There is nothing that is hidden from God. Our very secrets are near to him. Therefore, let us do everything as those who have him dwelling in us. (Letter to the Ephesians 15)
Let none of you cherish a grudge against his neighbor. Give no opportunity to the Gentiles, so that the whole multitude in God is not spoken evil of because of a few foolish men. For, "Woe to him by whose vanity my name is blasphemed among any" (Isaiah 52:5). (Letter to the Trallians 8)
You have taught others. Now I desire that those things may be confirmed [by your conduct], which in your instructions ye enjoin [on others]. Only pray both inward and outward strength for me, so that I may not only speak, but also be willing; and that I may not merely be called a Christian, but really be found to be one. For if I be truly found [a Christian], I may also be called one, and be then deemed faithful. (Letter to the Romans 3)
There are such men, confessing themselves to be Christians and admitting the crucified Jesus to be both Lord and Christ, yet not teaching his doctrines but those of the spirits of error. This causes those of us who are disciples of the true and pure doctrine of Jesus Christ to be more faithful and steadfast in the hope announced by him. (Dialogue with Trypho 35)
Lastly--are not the Church in their present state, a standing, public, perpetual denial of the gospel? Do they not stand out before the world, as a living, unanswerable contradiction of the gospel; and do more to harden sinners and lead them into a spirit of caviling and infidelity, than all the efforts of professed infidels from the beginning of the world to the present day? (unknown, quoted in an email newsletter without reference)