“The Evangelists insist on emphasising the historicity of [the Nativity of the Lord], because they want to say that Christ is a historical person. This means that Christ assumed real human flesh, and the incarnation was not merely seeming or imagined. In spite of its historicity, the event remains a mystery. We know that the Godman, perfect God and perfect man, exists, but it remains a mystery how the divine nature united with human nature in the person of the Logos. Moreover, what happened to the person of Christ, that the divine nature was united hypostatically with human nature, happened just once. Therefore St. John of Damaskos said that Christ is ‘the only new thing under the sun’. This means that since the creation of the world and man, nothing new has happened in the world. Everything is repeated. The birth of a man is a consequence and result of God’s words: ‘Let us make man in our image and likeness’, and ‘Be fruitful and multiply; fill the earth and subdue it’ (Gen 1, 26-38). The only new thing is the Godman Christ.”

– Met. Hierotheos Vlachos, The Feasts of the Lord.