The great majesty of Jesus being born is the incarnation of our Lord, that is, that God and man are now united in one person. This is a high and holy mystery and is worthy of a lifetime of contemplation.
Martin Luther gives us something to contemplate about this. While this quotation does not exhaust the mystery of the incarnation (far from it!), it is still worthy of pondering.
“These are marvelous things: to see a man and the lowliest creature humbled below all, to see the same creature sitting at the right hand of the Father and raised above all the angels, and to see Him in the bosom of the Father and soon subjected to the devil, as is stated in Ps. 8:5: ‘Thou hast made Him a little lower than the angels.’ Likewise in Eph. 4:9: ‘He had descended into the lower parts of the earth.’ This is a wonderful ascent and descent of the angels, to see the highest and the lowest completely united in one and the same Person, the highest God lying in the manger. Therefore the angels adore Him there, rejoice, and sing: ‘Glory to God in the highest’ (Luke 2:14). On the other hand, when they consider the lowliness of the human nature, they descend and sing: ‘And on earth peace.’” (Martin Luther. Luther’s Works: American Edition, Volume 5 (Lectures in Genesis, chapters 26-30), p 218.)