Augustine of Hippo, on 1John 4:2

“By this is the spirit of God known. Every spirit which confesseth that Jesus Christ is come in the flesh, is of God:”

“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.”

Imported from an open dataset — not yet checked against the printed edition.