Chrysostom on the Greatness of the Nativity

Reading through the Ancient Christian Devotional brought me to this passage by St. Chrysostom, that all great feasts have their origin in Jesus' Nativity, taken from 'On the Incomprehensible Nature of God 6.23-24,' I thought I would share with you:

A feast day is about to arrive, and it is the most holy and awesome of all feasts. It would be no mistake to call it the chief and mother of all holy days. What feast is that? It is the day of Christ's birth in the flesh. It is from this day that the feasts of the theophany, the sacred Pasch [Passover], the ascension and Pentecost had their source and foundation. Had Christ not been born in the flesh, he would not have been baptized, which is the theophany or manifestation. Nor would he have been crucified, which is the Pasch. Nor would he have sent down the Spirit, which is Pentecost. Therefore, just as different rivers arise from a single source, these other feasts have their beginnings in the birth of Christ.