The custom of setting up a Christmas crib in one’s home—not simply outside a church—reinforces the personal challenge represented by the Incarnation. The Incarnation changes everything in human history. We become different people because of it. In Francis’s day, many thought first of Jesus dying on the cross and only later about his birth in Bethlehem. Popularizing the crib reminded people of the great love that led to Jesus’s becoming one of us without compromising his divine nature. After that celebration in Greccio, participants could well have said, “This changes everything!” We could admire Jesus’s birth as an historical moment that becomes more distant with each passing year, or with Francis’s help, we can see it as an ongoing event and act accordingly.
— from the book Peace and Good: Through the Year with Francis of Assisi