In John 1:1-5, 14, the apostle John, whose Gospel is written from the perspective of an eyewitness, is proclaiming that Jesus Christ is the fulfillment of the Old Testament, that He has always existed, and that He is, indeed, God made man.
John poetically begins with the first three words of the Old Testament: “In the beginning…” Similarly, the first five verses of John attach Christ to the God who created the world in Genesis: “He was in the beginning with God” (John 1:2). Just as Genesis is a description of how God created the heavens and the earth, John, speaking of Jesus Christ, states “all things came to be through Him…” (John 1:3).
In Genesis 1:3-4, God created light and separated the light from the darkness. Similarly, John proclaims Jesus Christ as “the light [that] shines in the darkness, and the darkness has not overcome it” (John 1:5). In the first chapter of John, then, we learn that Jesus is God—the very same God who is described in Genesis and the rest of the Old Testament. John uses poetic parallelism to accomplish this task. As the United States Conference of Catholic Bishops notes in their footnote in John 1:14,“[t]he incarnate Word is the new mode of God’s presence among His people.”