For a moment I hesitated on the threshold. For the space of a breath I paused, unwilling to disturb her last ordinary moment, knowing that the next step would cleave her life: that this day would slice her story in two, dividing all the days before from all the ones to come. The artists would later depict the scene: Mary dazzled by the archangel, her head bowed in humble assent, awed by the messenger who condescended to leave paradise to bestow such an honor upon a woman, and mortal. Yet I tell you it was I who was dazzled, I who found myself agape when I came upon her— reading, at the loom, in the kitchen, I cannot now recall; only that the woman before me— blessed and full of grace long before I called her so— shimmered with how completely she inhabited herself, inhabited the space around her, inhabited the moment that hung between us. I wanted to save her from what I had been sent to say. Yet when the time came, when I had stammered...