St. Augustine and Amalarius of Metz: On the Octave of the Nativity

We understand two aspects of Christ's birth: the first is that Christ came to men; the second is that men came to Christ. Augustine writes on this subject in his first book On Christian Doctrine: "For we are not brought to him who is present everywhere, through space, but rather through good effort and good virtues. We would not be able to do this, unless wisdom had deigned to conform even to our great infirmity, that it might provide us with an example of how to live in no other way than in the guise of a man, since we are also men. But because we act wisely when we come to that wisdom, wisdom itself, when it comes to us, is thought by proud men to have acted foolishly. And because we regain our health when we come to it, wisdom, when it comes to us, is thought to be almost weak. But 'the foolishness of God is wiser than men, and the weakness of God is stronger than men.' Since therefore wisdom is our homeland, it has also made itself a path for us to the homeland. And since it is present everywhere to the pure and healthy interior eye, it also deigned to appear to the carnal eyes of those whose interior eye is infirm and unclean. 'For since in the wisdom of God the world, by wisdom, was not able to know God, it pleased God by the foolishness of our preaching to save them that believe.' He is therefore said to have come to us not by moving through space, but by appearing to mortals in mortal flesh. Thus, he came to a place where he already was, because 'he was in the world and the world was made through him’.

We commemorate Christ's coming to men on the feast of his Nativity, and the coming of men to Christ on the octave of his nativity. This is easily recognized through the antiphons that are sung for Matins. The first antiphon for the Lord's Nativity, GenuitPuerPera regem, tells of the Lord's pure birth. The first for the Lord's octave says: "O admirable exchange." When it speaks of "exchange," it shows that something is given and something received. Christ gave his divinity and received our humanity. We commemorate what he gave on his Nativity, and what he received, on the octave. The members, joined to the head, are commended in this feast.