In 2000, Pope John Paul II canonized the great 20th century visionary of Divine Mercy, Sister Faustina Kowalska, and proclaimed the Sunday after Easter to be celebrated annually as Divine Mercy Sunday. In 2006, Pope Benedict stressed that Divine Mercy is not a secondary devotion, but an integral dimension of Christian faith and prayer. Now Pope Francis has proclaimed an extraordinary Jubilee Year of Mercy, which will begin on December...