2 John 1:7

Epistle of Ignatius to the Antiochians

And he that rejects the incarnation, and is ashamed of the cross for which I am in bonds, this man is antichrist.[24]

Irenaeus Against Heresies Book III

These are they against whom the Lord has cautioned us beforehand; and His disciple, in his Epistle already mentioned, commands us to avoid them, when he says: "For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist. Take heed to them, that ye lose not what ye have wrought."[296]

Tertullian On Fasting

And how is it that he enjoins duties which belong to our God, and enjoins them to be offered to none other than our God? Either contend that the devil works with our God, or else let the Paraclete be held to be Satan. But you affirm it is "a human Antichrist: "for by this name heretics are called in John.[90]