Boff doesn't claim as some do that this religion is better - it isn't - but it is unique. Yes, there are fundamental similarities in our respective calls to justice and compassion. And yes other faith traditions have their unique insights into the holy, too. But the revelation of the incarnation - the Feast of the Nativity - is that God is with us in our shared humanity. Of course there is a transcendent dimension to the sacred, but the scandal of the Christian tradition moves beyond generalities to the particulars of compassion and justice in a unique way.
The photograph of a sculpture outside St. Martins in the Fields in London makes this clear. So does Jean Vanier's insistence that the way God comes into our humanity is through cherished vulnerability: God comes to us in a tiny package. And God is nourished through the very real flesh of his mother's breasts. This graphic recently posted on Face Book kicks up the incarnational truths of Christmas. There is littleness and earthiness, vulnerability and intimacy, the invitation to cherish, nourish and change. I still don't have my quiet and tender Christmas Eve homily yet. But I've been walking around with these ideas for a few days praying they might lead me somewhere faithful.