Cyprian of Carthage, Treatises Treatise 1

When the Lord warns us, 'You are the salt of the earth' (Matt 5:13), and commands us to be simple in innocence yet prudent in that same simplicity, what else should we do, beloved brothers, than take care? We must watch with anxious hearts, discerning and guarding against the cunning enemy's treacherous plots, lest we who have put on Christ, the wisdom of God the Father, appear less wise in protecting our salvation. It is not only open persecution that threatens, nor only those assaults that attack God's servants plainly and throw them down. Caution comes easily when danger is visible, and the mind readies itself for battle when the adversary shows his face. The enemy is far more to be feared and avoided when he steals in secretly, disguising himself with a façade of peace and slipping in by hidden approaches — which is why he bears the name of the serpent. This is his constant craft: a blind, concealed deceit that entraps mankind. From the very beginning of the world he deceived, coaxing simple souls with lying words and catching them in unsuspecting credulity. He even dared to tempt the Lord Himself, stealing close in another attempt to deceive; but he was recognized and repulsed, thrown down because he had been detected. This gives us our pattern: flee the way of the old man, plant our feet in the steps of the living Christ, so that we do not fall unawares again into death's snare, but, foreseeing the danger, may lay hold of immortality.

And how can we lay hold of immortality unless we keep the commandments of Christ, by which death is overcome and conquered? He Himself warns and says, 'If you wish to enter life, keep the commandments,' and again, 'If you do what I command you, I no longer call you servants, but friends' (John 15:14-15). These, finally, He calls strong and stable, founded on a massive rock, set fast with immovable, unshakable firmness against every tempest and whirlwind of the world. 'Whoever hears my words and does them,' He says, 'I will liken to a wise man who built his house on rock. The rain fell, the rivers rose, the winds blew and beat against that house, and it did not fall, because it had been founded on rock' (Matt 7:24-27). We must therefore stand firm on His words, learning and doing whatever He taught and commanded. How can someone claim to believe in Christ while refusing to do what Christ commanded? Where will such a one find the reward of faith who will not keep the faith of the commandment? He must waver and wander, seized by a spirit of error and blown about like dust before the wind; he will never advance toward salvation who does not hold to the truth of the saving way.

But we must be on guard, beloved brothers, not only against what is open and plain, but also against what deceives with the subtlety of cunning fraud. What could be more cunning, more subtle, than this: the enemy, detected and thrown down by Christ's advent, after the light has come to the Gentiles and the saving light has shone for mankind — so that the deaf receive the hearing of spiritual grace, the blind open their eyes to God, the weak recover eternal health, the lame run to the Church, the mute pray with clear voices — seeing idols abandoned and his own seats and temples deserted by the multitude of believers, he devises a new fraud to deceive the unwary under the very title of the Christian name? He invents heresies and schisms to subvert faith, corrupt truth, and tear apart unity. Those he cannot hold in the blindness of the old way, he encircles and deceives by the error of a new way. He snatches men from the very Church; and while they think they have approached the light and escaped the world's darkness, he pours fresh darkness upon them, unknown to them, so that — not standing with the Gospel of Christ, its observance, and its law — they still call themselves Christians, and walking in darkness believe they possess the light. The adversary flatters and deceives, transforming himself, as the Apostle says, into an angel of light, and disguising his ministers as ministers of righteousness. They declare night to be day, destruction to be salvation, despair under the pretext of hope, perfidy under the pretext of faith, antichrist under the name of Christ — so that, by speaking what sounds plausible, they frustrate the truth with subtlety. This happens, beloved brothers, when we do not return to the source of truth, nor seek the Head, nor preserve the doctrine of the heavenly Master.