Nicene and Post-Nicene Fathers, Ser. II, Vol. IX:
John of Damascus: Exposition of the Orthodox Faith.: How the Only-begotten Son of God is called first-born.

Chapter VIII.—How the Only-begotten Son of God is called first-born.

He who is first begotten is called first-born 2281 , whether he is only-begotten or the first of a number of brothers. If then the Son of God was called first-born, but was not called Only-begotten, we could imagine that He was the first-born of creatures, as being a creature 2282 . But since He is called both first-born and Only-begotten, both senses must be preserved in His case. We say that He is first-born of all creation 2283 since both He Himself is of God and creation is of God, but as He Himself is born alone and timelessly of the essence of God the Father, He may with reason be called Only-begotten Son, first-born and not first-created. For the creation was not brought into being out of the essence of the Father, but by His will out of nothing 2284 . And He is called First-born among many brethren 2285 , for although being Only-begotten, He was also born of a mother. Since, indeed, He participated just as we ourselves do in blood and flesh and became man, while we too through Him became sons of God, being adopted through the baptism, He Who is by nature Son of God became first-born amongst us who were made by adoption and grace sons of God, and stand to Him in the relation of brothers. Wherefore He said, I ascend unto My Father and your Father 2286 . He did not say “our Father,” but “My Father,” clearly in the sense of Father by nature, and “your Father,” in the sense of Father by grace. And “My God and your God 2287 .” He did not say “our God,” but “My God:” and if you distinguish with subtle thought that which is seen from that which is thought, also “your God,” as Maker and Lord.

Footnotes

See the Scholiast on Gregory Nyssenus in Cod. Reg. 3451.

Vid. apud Greg. Nyss., bk. iii., contr. Eunom.

Col. i. 15.

Athan., Expos. Fidei.

Rom. viii. 29.

St. John xx. 17.

John 20.17