1 John 4:2

There remains then the test by which it is to be proved to be the Spirit of God. He has indeed set down a sign, and this, be-like, difficult: let us see, however. We are to recur to that charity; it is that which teacheth us, because it is the unction. However, what saith he here? "Prove the spirits, whether they be from God: because many false prophets have gone out into this world." Now there are all heretics and all schismatics. How then am I to prove the spirit? He goes on: "In this is known the Spirit of God." Wake up the ears of your heart. We were at a loss; we were saying, Who knows? who discerns? Behold, he is about to tell the sign.

"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."

What are we to do then? By what to discern them? Be very attentive; let us go together in heart, and knock. Charity herself keeps watch; for it is none other than she that shall knock, she also that shall open: anon ye shall understand in the name of our Lord Jesus Christ. Already ye have heard that it was said above, "Whoso denieth that Jesus Christ is come in the flesh, the same is an antichrist." There also we asked, Who denies? because neither do we deny, nor do those deny. And we found that some do in their deeds deny; and we brought testimony from the apostle, who saith, "For they confess that they know God, but in their deeds deny Him." 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?