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 to be through him, and without him nothing came to be. What came to be through him was life, and this life was the light of the human race; the light shines in the darkness, and the darkness has not overcome it. A man named John was sent from God. He came for testimony, to testify to the light, so that all might believe through him. He was not the light, but came to testify to the light. The true light, which enlightens everyone, was coming into the world. He was in the world, and the world came to be through him, but the world did not know him. He came to what was his own, but his own people did not accept him. But to those who did accept him he gave power to become children of God, to those who believe in his name, who were born not by natural generation nor by human choice nor by a man's decision but of God. And the Word became flesh and made his dwelling among us, and we saw his glory, the glory as of the Father's only Son, full of grace and truth. John testified to him and cried out, saying, "This was he of whom I said, 'The one who is coming after me ranks ahead of me because he existed before me.'" From his fullness we have all received, grace in place of grace, because while the law was given through Moses, grace and truth came through Jesus Christ. No one has ever seen God. The only Son, God, who is at the Father's side, has revealed him. (Jn 1:1-18)
The Word was eternal, all pervading, beginning of everything and was God. It is amazing that such a word becomes a small word. A word that could be seen by people; and felt by people; and understood by people has come to dwell among men. Incarnation theology is given beautifully in these words.
This word was light to the people. Word was the light in the dark. The prime duty of the word was to give light to the world. We know well that light was the first of creation to show to the believers that light is essential and only through light that things are made visible.
First the author speaks about the word (who) then speaks about light (what it does) and then he turns to where the word is active. It is in the world. The word comes to the world and the world does not receive him. The word comes to give life to the world but the world rejects him. The word has come to remain in the world and to give life to the people.