John's cliff-note of what's to come.
Commentaries agree that verses 1-18 are John’s prologue to his gospel account. It seems to be sort of a cliff-note summary of the things to come with special emphasis on Jesus Chris. My assumption is that John was preparing his readers and giving them a kind of foundation in order to build the story of the gospel.
John MacArthur categorizes this section into six groups that I think best explains John’s prologue: the eternal Christ (1-3), the incarnate Christ (4-5), the forerunner of Christ (6-8), the unrecognized Christ (9-11), the omnipotent Christ (12-13), and the glorified Christ (14-18).1
In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things came into being through Him, and apart from Him nothing came into being that has come into being. In Him was life, and the life was the Light of men. The Light shines in the darkness, and the darkness did not comprehend it.
There came a man sent from God, whose name was John. He came as a witness, to testify about the Light, so that all might believe through him. He was not the Light, but he came to testify about the Light.
There was the true Light which, coming into the world, enlightens every man. He was in the world, and the world was made through Him, and the world did not know Him. He came to His own, and those who were His own did not receive Him. But as many as received Him, to them He gave the right to become children of God, even to those who believe in His name, who were born, not of blood nor of the will of the flesh nor of the will of man, but of God.
And the Word became flesh, and dwelt among us, and we saw His glory, glory as of the only begotten from the Father, full of grace and truth. John testified about Him and cried out, saying, “This was He of whom I said, ‘He who comes after me has a higher rank than I, for He existed before me.’” For of His fullness we have all received, and grace upon grace. For the Law was given through Moses; grace and truth were realized through Jesus Christ. No one has seen God at any time; the only begotten God who is in the bosom of the Father, He has explained Him.