1 John 4:3

Thus then let us now also make the enquiry in the deeds not in the tongue. What is the spirit that is not from God? That "which denieth that Jesus Christ is come in the flesh." And what is the spirit that is from God? That "which confesseth that Jesus Christ is come in the flesh." Who is he that confesseth that Jesus Christ is come in the flesh? Now, brethren, to the mark! let us look to the works, not stop at the noise of the tongue. Let us ask why Christ came in the flesh, so we get at the persons who deny that He is come in the flesh. If thou stop at tongues, why, thou shalt hear many a heresy confessing that Christ is come in the flesh: but the truth convicteth those men. Wherefore came Christ in the flesh? Was He not God? Is it not written of Him, "In the beginning was the Word, and the Word was with God, and the Word was God?" Was it not He that did feed angels, is it not He that doth feed angels? Did He not in such sort come hither, that He departed not thence? Did He not in such sort ascend, that He forsook not us? Wherefore then came He in the flesh? Because it behooved us to have the hope of resurrection shown unto us. God He was, and in flesh He came; for God could not die, flesh could die; He came then in the flesh, that He might die for us. But how died He for us? "Greater charity than this hath no man, that a man lay down his life for his friends." Charity therefore brought Him to the flesh. Whoever therefore has not charity denies that Christ is come in the flesh. Here then do thou now question all heretics. Did Christ come in the flesh? "He did come; this I believe, this I confess." Nay, this thou deniest. "How do I deny? Thou hearest that I say it!" Nay, I convict thee of denying it. Thou sayest with the voice, deniest with the heart; sayest in words, deniest in deeds. "How," sayest thou, "do I deny in deeds?" Because the end for which Christ came in the flesh, was, that He might die for us. He died for us, because therein He taught much charity. "Greater charity than this hath no man, that a man lay down his life for his friends." Thou hast not charity, seeing thou for thine own honor dividest unity. Therefore by this understand ye the spirit that is from God. Give the earthen vessels a tap, put them to the proof, whether haply they be cracked and give a dull sound: see whether they ring full and clear, see whether charity be there. Thou takest thyself away from the unity of the whole earth, thou dividest the Church by schisms, thou rendest the Body of Christ. He came in the flesh, to gather in one, thou makest an outcry to scatter abroad. This then is the Spirit of God, which saith that Jesus is come in the flesh, which saith, not in tongue but in deeds, which saith, not by making a noise but by loving. And that spirit is not of God, which denies that Jesus Christ is come in the flesh; denies, here also, not in tongue but in life; not in words but in deeds. It is manifest therefore by what we may know the brethren. Many within are in a sort within; but none without except he be indeed without.

"And every spirit, qui solvit Christum, which does away with Christ that He came in the flesh, is not of God." A doing away in deeds is meant. What has he shown thee? "That denieth:" in that he saith, "doeth away" (or, "unmaketh"). He came to gather in one, thou comest to unmake. Thou wouldest pull Christ's members asunder. How can it be said that thou deniest not that Christ is come in the flesh, who rendest asunder the Church of God which He hath gathered together? Therefore thou goest against Christ; thou art an antichrist. Be thou within, or be thou without, thou art an antichrist: only, when thou art within, thou art hidden; when thou art without, thou art made manifest. Thou unmakest Jesus and deniest that He came in the flesh; thou art not of God. Therefore He saith in the Gospel: "Whoso shall break one of these least commandments, and shall teach so, shall be called least in the kingdom of heaven." What is this breaking? What this teaching? A breaking in the deeds and a teaching as it were in words. "Thou that preachest men should not steal, dost thou steal?" Therefore he that steals breaks or undoes the commandment in his deed, and as it were teaches so: "he shall be called least in the kingdom of heaven," i.e. in the Church of this present time. Of him it is said, "What they say do ye; but what they do, that do not ye."

"But he that shall do, and shall teach so, shall be called great in the kingdom of heaven." From this, that He has here said, fecerit, "shall do," while in opposition to this He has there said solverit, meaning non fecerit, "shall not do, and shall teach so" - to break, then, is, not to do - what doth He teach us, but that we should interrogate men's deeds, not take their words upon trust?

"Hereby is known the Spirit of God: every spirit that confesseth that Jesus Christ is come in the flesh is of God: and every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is the antichrist, of whom ye have heard that he should come; and even now already is he in this world." Our ears, so to say, are on the alert for discerning of the spirits; and we have been told something, such that thereby we discern not a whit the more. For what saith he? "Every spirit that confesseth that Jesus Christ came in the flesh, is of God." Then is the spirit that is among the heretics, of God, seeing they "confess that Jesus Christ came in the flesh"?

Aye, here perchance they lift themselves up against us, and say: Ye have not the Spirit from God; but we confess "that Jesus Christ came in the flesh:" but the apostle here hath said that those have not the Spirit of God, who confess not "that Jesus Christ came in the flesh." Ask the Arians: they confess "that Jesus Christ came in the flesh:" ask the Eunomians; they confess "that Jesus Christ came in the flesh:" ask the Macedonians; they confess "that Jesus Christ came in the flesh:" put the question to the Cataphryges; they confess "that Jesus Christ came in the flesh:" put it to the Novatians; they confess "that Jesus Christ came in the flesh." Then have all these heresies the Spirit of God? Are they then no false prophets? Is there then no deception there, no seduction there? Assuredly they are antichrists; for "they went out from us, but were not of us."