The Feast of Divine Mercy has its origins in the writings of St. Faustina Kowalska, canonized by Pope John Paul II on April 30, 2000. St. Faustina was an uneducated Polish nun who, in obedience to her spiritual director, wrote a 600-page diary recording revelations she received about God's mercy. Jesus promised to grant complete forgiveness of sins and punishment on the Feast of Mercy; this is referenced to three times in St. Faustina's diary:
“I want to grant a complete pardon to the souls that will go to Confession and receive Holy Communion on the feast of my mercy.”
“Whoever approaches the Fountain of Life on this day will be granted complete forgiveness of sins and punishment.”
“The soul that will go to Confession and receive Holy Communion will obtain complete forgiveness of sins and punishments.”
Jesus also promises:
“On that day the very depths of My tender mercy are open. I pour out a whole ocean of graces upon those souls who approach the fountain of My mercy. The soul that will go to Confession and receive Holy Communion shall obtain complete forgiveness of sins and punishments. On that day all the Divine floodgates through which graces flow are opened.”
“Yes, the first Sunday after Easter is the Feast of Mercy, but there must also be acts of mercy… I demand from you deeds of mercy, which are to arise out of your love for Me. You are to show mercy to your neighbors always and everywhere. You must not shrink from this or try to excuse or absolve yourself from it.”
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