Irenaeus was a theologian and apologist during the 2nd century. He lived in Asia Minor (Turkey) before becoming Bishop of Lyons (in France). While in Asia Minor, Irenaeus was was taught by Polycarp who was the Bishop of Smyrna and who was himself trained by the Apostle John. He even made Parchment and Pen’s Top Ten Theologian list.
Around 180 AD Irenaues wrote a treatise – Against Heresies – which defended the Christian faith handed down by the apostles against various heretical teachings at the time. As he writes about Christ’s coming into this world one can see the influences of the Gospel of John. Keep in mind as well that this was written nearly 150 years before the Council of Nicea.
As it has been clearly demonstrated that the Word, who existed in the beginning with God, by whom all things were made, who was also always present with mankind, was in these last days, according to the time appointed by the Father, united to His own workmanship, inasmuch as He became a man liable to suffering, [it follows] that every objection is set aside of those who say, “If our Lord was born at that time, Christ had therefore no previous existence.” For I have shown that the Son of God did not then begin to exist, being with the Father from the beginning; but when He became incarnate, and was made man, He commenced afresh the long line of human beings, and furnished us, in a brief, comprehensive manner, with salvation; so that what we had lost in Adam—namely, to be according to the image and likeness of God—that we might recover in Christ Jesus.
For as it was not possible that the man who had once for all been conquered, and who had been destroyed through disobedience, could reform himself, and obtain the prize of victory; and as it was also impossible that he could attain to salvation who had fallen under the power of sin,—the Son effected both these things, being the Word of God, descending from the Father, becoming incarnate, stooping low, even to death, and consummating the arranged plan of our salvation … But if, not having been made flesh, He did appear as if flesh, His work was not a true one. But what He did appear, that He also was: God recapitulated in Himself the ancient formation of man, that He might kill sin, deprive death of its power, and vivify man; and therefore His works are true.
… that He is Himself in His own right, beyond all men who ever lived, God, and Lord, and King Eternal, and the Incarnate Word, proclaimed by all the prophets, the apostles, and by the Spirit Himself, may be seen by all who have attained to even a small portion of the truth. Now, the Scriptures would not have testified these things of Him, if, like others, He had been a mere man. But that He had, beyond all others, in Himself that pre-eminent birth which is from the Most High Father, and also experienced that pre-eminent generation which is from the Virgin, the divine Scriptures do in both respects testify of Him: … that He was despised among the people, and humbled Himself even to death and that He is the holy Lord, the Wonderful, the Counsellor, the Beautiful in appearance, and the Mighty God, coming on the clouds as the Judge of all men;—all these things did the Scriptures prophesy of Him.
Excerpts from Against Heresies Book III, chapters 18 and 19