The so-called “Fátima prayer”—O my Jesus, forgive us our sins, save us from the fires of hell, and lead all souls to heaven, especially those in most need of thy mercy, amen—due primarily to its widespread use as a rosary decade prayer, surely ranks among the Church's most popular prayers. Despite its brevity, it is a prayer of remarkable theological depth—not to mention, daring. In the space of just twenty-nine words, it broaches some of the great themes of Christianity: sin, forgiveness, mercy, heaven, hell. It also touches on two hot topics within contemporary Catholic discussion—having a personal relationship with "my Jesus,' and the permissibility of hoping that "all souls" may ultimately be saved.O My Jesus is a concise work of both popular theology and spiritual writing not unlike the kinds of interpretive commentaries on key prayers produced by Christian theologians since at least the third century.†