The Gospel according to John is a conundrum. It deals with the life of Jesus, but in such a different way than the other three. The other three Gospels deal with Jesus in the here and now on earth, Matthew and Luke going so far as to provide infancy narratives. John is way different. The initial part of the first chapter, selected for reading at today's Mass (see here for the text) is known as the Prologue, and it deals not so much as the human side of the experience as it does the Divine. The Word is eternal, the Word is God, the Word became flesh. The themes are cosmic in nature, eternity, light versus dark, life versus death.
Buried, or rather, an undercurrent, in this section and echoing through the entire Gospel is the theme of God's love, a love so all-encompassing that God took on humanity to reconcile them to Himself, if they would take the plunge. Humanity was familiar with law and morals and conscience and behavioural codes. In fact, the Prologue states that these things were especially pointed out by Moses, considered Israel's greatest Prophet. It then goes on to state that there is something more, grace and truth, that is, God's reconciling love and willingness to share Himself, His Truth, with those who would seek it through Jesus the Messiah, a human born of humans, who also was the Eternal Son, the Word, existing before all creation, and having taken part in the wonder of creation.
We heard about Mary, the Angels, the Shepherds, Joseph, the Magi, but here, here we hear of God's part in the Christmas story, a story of grace and truth.