Rejoice!

"Dearly beloved brethren, Unto us is born this day a Saviour, Let us rejoice. It would be unlawful to be sad to day, for today is Life's Birthday; the Birthday of that Life, Which, for us dying creatures, taketh away the sting of death, and bringeth the bright promise of the eternal gladness hereafter. It would be unlawful for any man to refuse to partake in our rejoicing. All men have an equal share in the great cause of our joy, for, since our Lord, Who is the destroyer of sin and of death, findeth that all are bound under the condemnation, He is come to make all free. Rejoice, O thou that art holy, thou drawest nearer to thy crown! Rejoice, O thou that art sinful, thy Saviour offereth thee pardon! Rejoice also, O thou Gentile, God calleth thee to life! For the Son of God, when the fulness of the time was come, which had been fixed by the unsearchable counsel of God, took upon Him the nature of man, that He might reconcile that nature to Him Who made it, and so the devil, the inventor of death, is met and beaten in that very flesh which hath been the field of his victory."

-Pope St. Leo the Great, Matins for the Feast of the Nativity, Nocturn II