It is a newspaper image I will never forget. And for me it is an image of Advent. The time was the early 1990s. The place was Sarajevo — the gutted, bombed out epicenter of the Balkan War — when ethnic violence had destroyed beauty and buildings and any sense of human community. One day, a man put on his tuxedo, picked up his cello and a chair, and went and sat at the central intersection of town — in the cross fire of hatred and brokenness and devastation — and there he played his cello for hours — defying all reason, embracing all hope — proclaiming through his melancholy melody that darkness and death never have the final word.

Today, my friends, is the first day of the Christian year, the beginning of Advent, the season of waiting where God is the darkness that promises light. Unlike …