On the Unity of the Catholic Church 3

But we must beware not only of things that are open and manifest, but also of those that deceive by the subtlety of crafty fraud. And what is more crafty or more subtle than this? The enemy, exposed and overthrown by the coming of Christ, after light came to the nations and the saving light shone out for the preservation of men, so that the deaf received the hearing of spiritual grace, the blind opened their eyes to the Lord, the sick recovered with eternal health, the lame ran to the church, the dumb prayed with clear voices and prayers, seeing the idols abandoned and his seats and temples deserted by the great multitude of believers, devised a new fraud, to deceive the unwary under the very title of the Christian name. He invented heresies and schisms, by which to overthrow faith, corrupt truth, and split unity. Those whom he cannot hold in the blindness of the old way, he circumvents and deceives by the error of a new road. He snatches men from the church itself, and, while they seem to themselves to have already drawn near to the light and escaped the night of the world, he pours other darkness over them again without their knowing it; so that, not standing with the gospel of Christ and with its observance and law, they call themselves Christians, and, walking in darkness, think they have the light, while the adversary flatters and deceives them, who, according to the apostle's word, transforms himself into an angel of light and suborns his ministers as ministers of righteousness, who assert night for day, destruction for salvation, despair under the pretext of hope, faithlessness under the pretence of faith, Antichrist under the name of Christ; so that, while they tell lies that look like truth, they frustrate the truth by their subtlety. This happens, dearest brothers, because there is no return to the source of truth, nor is the head sought, nor is the teaching of the heavenly Master kept.