Ignatius on False Teachers

But some most worthless persons are in the habit of carrying about the name [of Jesus Christ] in wicked guile, while yet they practise things unworthy of God, and hold opinions contrary to the doctrine of Christ, to their own destruction, and that of those who give credit to them, whom you must avoid as ye would wild beasts. For “the righteous man who avoids them is saved for ever; but the destruction of the ungodly is sudden, and a subject of rejoicing.” For “they are dumb dogs, that cannot bark,” raving mad, and biting secretly, against whom ye must be on your guard, since they labour under an incurable disease. …

I have heard of some who have passed in among you, holding the wicked doctrine of the strange and evil spirit; to whom ye did not allow entrance to sow their tares, but stopped your ears that ye might not receive that error which was proclaimed by them, as being persuaded that that spirit which deceives the people does not speak the things of Christ, but his own, for he is a lying spirit. But the Holy Spirit does not speak His own things, but those of Christ, and that not from himself, but from the Lord; even as the Lord also announced to us the things that He received from the Father. …

But the spirit of deceit preaches himself, and speaks his own things, for he seeks to please himself. He glorifies himself, for he is full of arrogance. He is lying, fraudulent, soothing, flattering, treacherous, rhapsodical, trifling, inharmonious, verbose, sordid, and timorous. …

Do not err, my brethren. Those that corrupt families shall not inherit the kingdom of God. And if those that corrupt mere human families are condemned to death, how much more shall those suffer everlasting punishment who endeavour to corrupt the Church of Christ, for which the Lord Jesus, the only-begotten Son of God, endured the cross, and submitted to death! Whosoever, “being waxen fat,” and “become gross,” sets at nought His doctrine, shall go into hell. In like manner, every one that has received from God the power of distinguishing, and yet follows an unskilful shepherd, and receives a false opinion for the truth, shall be punished. “What communion hath light with darkness? or Christ with Belial? Or what portion hath he that believeth with an infidel? or the temple of God with idols? ” And in like manner say I, what communion hath truth with falsehood? or righteousness with unrighteousness? or true doctrine with that which is false?…

Let no one be anointed with the bad odour of the doctrine of [the prince of] this world; let not the holy Church of God be led captive by his subtlety, as was the first woman. Why do we not, as gifted with reason, act wisely? When we had received from Christ, and had grafted in us the faculty of judging concerning God, why do we fall headlong into ignorance? and why, through a careless neglect of acknowledging the gift which we have received, do we foolishly perish?

Epistle of Ignatius to the Ephesians