By Brian Kranick, Catholic Exchange - Divine Mercy Sunday may be the greatest day of the year because of the immeasurable amount of grace Jesus promised to pour forth on this day. In the private revelation accepted publicly by the Church, Jesus made a specific promise to Saint Faustina about Divine Mercy Sunday: “On that day . . . The soul that will go to Confession and receive Holy Communion shall obtain complete forgiveness of sins and punishment.” (Diary, 699)