Gnostic - Jesus didn't come in the Flesh

We can see in the scriptures that the Apsotles were giving us clear warning as to the false teachers that were rising up and decieving many.

1 John 4:1-2
2 Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. 2 By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God;

Now we can see Irenaeus refute this exact same teaching.

Irenaeus [A.D. 120–202.]

 

Against Heresies: Book I
Chapter IX.--Refutation of the impious interpretations of these heretics.

http://www.ccel.org/ccel/schaff/anf01.ix.ii.x.html

 

But that the apostle did not speak concerning their conjunctions, but concerning our Lord Jesus Christ, whom he also acknowledges as the Word of God, he himself has made evident. For, summing up his statements respecting the Word previously mentioned by him, he further declares, "And the Word was made flesh, and dwelt among us." But, according to their hypothesis, the Word did not become flesh at all, inasmuch as He never went outside of the Pleroma, but that Saviour [became flesh] who was formed by a special dispensation [out of all the Æons], and was of later date than the Word.