It’s a familiar prayer:Angel of God, my guardian dear, to whom God's love commits me here, ever this day/night be at my side, to light, to guard, to rule and guide. Amen.We probably all learned this prayer when we were children, and the image of a personal guardian angel—a celestial being appointed to watch over us—enfolded our childhood fears and joys. As adults, though, many of us have drifted away from that childlike confidence in a protector, but as we celebrate the Fea...