John 4:1

Irenaeus Against Heresies Book III

Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God; and every spirit which separates Jesus Christ is not of God, but is of antichrist."[297]

Tertullian Against Marcion Book V

by the Apostle John, who says that "already many false prophets are gone out into the world," the fore-runners of Antichrist, who deny that Christ is come in the flesh,[740]

Tertullian On Modesty

withal, issued any such proclamation in favour of sinners; as when He permitted contact even with his own body to the "woman, a sinner,"-washing, as she did, His feet with tears, and wiping them with her hair, and inaugurating His sepulture with ointment; as when to the Samaritaness-not an adulteress by her now sixth marriage, but a prostitute-He showed (what He did show readily to any one) who He was;[119]

Dubious Hippolytus Fragments

Believe not every spirit, because many false prophets are gone out into the world."[37]