The Divine Mercy Chaplet is prayed on the beads of the Rosary, was taught to Sister Faustina by our Lord Jesus Himself, and carries great promises and graces. Our Lord Jesus dictated this prayer to Saint Faustina on 13th September 1935 (Diary of St Faustina, paragraph 476).
Jesus said that whenever this chaplet of the Divine Mercy is prayed that His Heart is stirred to its very depths, that He will protect all who pray it during their life and especially in the hour of their death, that He will grant anything that is compatible with His Divine will through this prayer, that the whole world is brought closer to God when this Chaplet is prayed (929), and that when this prayer is said in the presence of a dying person that “I [Jesus] will stand between My Father and the dying person, not as the just judge but as the merciful Saviour.” (Diary of St Faustina, 1541)
This is how our Lord Jesus taught Sister Faustina this prayer:
“The next morning, when I entered chapel, I heard these words interiorly: Every time you enter the chapel, immediately recite the prayer which I taught you yesterday. When I had said the prayer, in my soul I heard these words: This prayer will serve to appease My wrath. You will recite it for nine days, on the beads of the rosary, in the following manner: First of all, you will say one OUR FATHER and HAIL MARY and the I BELIEVE IN GOD. Then on the OUR FATHER beads you will say the following words: “Eternal Father, I offer You the Body and Blood, Soul and Divinity of Your dearly beloved Son, Our Lord Jesus Christ, in atonement for our sins and those of the whole world.” On the HAIL MARY beads you will say the following words: “For the sake of His sorrowful Passion have mercy on us and on the whole world.” In conclusion, three times you will recite these words: “Holy God, Holy Mighty One, Holy Immortal One, have mercy on us and on the whole world.””
Diary of Saint Faustina, paragraph 476.
Read more: History of Divine Mercy