The sermon centers on the theological significance of the Incarnation as revealed in the Gospel of John, emphasizing that the eternal Word—divine, co-existent with God, and the source of all creation—became flesh in Jesus Christ, not as a mere human but as God fully embodied. Through a reflective exploration of John the Apostle's identity as a fisherman, a writer, a close relative of Jesus, and the beloved disciple, the preacher highlights how John's life and writings uniquely testify to Christ's dual nature: fully God and fully man. The message underscores that John's Gospel, though lacking the nativity details of Matthew and Luke, presents the profound truth of the Incarnation in its most essential form—'the Word became flesh'—which is the heart of Christmas. The sermon calls believers to read John at Christmas not only to marvel at God's majestic humility in becoming human but also to be drawn into saving faith, recognizing that salvation comes not through human effort but through grace, by believing in Jesus alone as the divine Savior who took on human suffering and sin to redeem humanity.

The sermon presents the Incarnation as the core of Christmas, drawing from John's Gospel to affirm that the eternal Word became fully human without ceasing to be divine, a truth that demands faith, evokes worship, and reveals God's ultimate love for humanity.