From 1931 to 1938 Our Lord revealed the secrets of His great mercy to St. Faustina. He designated the first Sunday after Easter as the Feast of the Divine Mercy of God. In preparation of this Feast, He asked that a Novena be started on Good Friday, a Novena which asks for prayers each of the nine days for a different group of souls in order to immerse them in the sea of God’s Mercy! Mass, Confession, Communion are required on Mercy Sunday, the first Sunday after Easter. Our Lord promised to the souls who follow these requests a complete remission of sin and punishment! Our Lord thus instructed Sister Faustina: “My daughter, speak to the whole world of My incomprehensible Mercy. I desire that the Feast be a refuge and a shelter for all souls, especially for poor sinners. The very depths of My Mercy will be opened on that day. I will pour out a sea of graces upon those souls that will approach the font of My Mercy. Those who go to confession and receive Holy Communion on Mercy Sunday, the first Sunday after Easter, will obtain complete remission of sins and punishment. Let no soul fear to come to Me, even though its sins be as scarlet. Tell ailing mankind to draw close to My Merciful Heart and I will fill it with peace. Mankind will not find peace until it turns with confidence to My Mercy.”

https://www.tldm.org/news4/divinemercy.htm
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FIRST DAY - Good Friday, April 10, 2020
Let us pray that God may deign to show His Mercy to all mankind.
O Most Merciful Jesus, for Whom it its most proper to be merciful unto us and to forgive us, look not upon our sins, but upon the hope which we have in Thy infinite goodness. Receive us all into the abode of Thy Most Merciful Heart and do not permit anyone to depart there from for all eternity for the love which unites Thee with the Father and the Holy Spirit. “Show us Thy mercy, O Lord, just as we trust in Thy Holy Name, for Thou art all powerful, most kind, patient, faithful, good and merciful.” Eternal Father, view all mankind with a merciful eye, and especially the poor sinners, whose only hope is the Most Merciful Heart of Thy Son and Our Lord and Savior Jesus Christ. Through His sorrowful Passion stretch Thy mercy over us, that together we may glorify Thy omnipotence for all eternity. Amen. Our Father ... Hail Mary ... Glory be to the Father ...
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SECOND DAY - Holy Saturday, April 11, 2020
Let us pray for the clergy of all ranks, through whom the Mercy of God is poured out on all mankind.
Most Merciful Jesus, from Whom all good proceeds, increase Thy graces in the souls of Thy priests and religious, that they may worthily and fruitfully accomplish their tasks in Thy Vineyard, and that they may lead all by words and example to a rightful cult of Divine Mercy for all eternity. The Font of Mercy and Love Divine Resides in the hearts of the humble and the innocent, Till, bathed in the wavelets of God’s Mercy, They sparkle like the stars and the morning dew. Eternal Father, cast Thy Merciful glance upon the laborers in Thy Vineyard—on the souls of priests, nuns and brothers, who are the special beloved of Thy Son and Our Lord Jesus Christ. Adorn them with the power of Thy blessing and grant them special light, that they may consistently lead others along the path of salvation and may obtain for them all the graces of Thy Mercy. Amen. Our Father ... Hail Mary ... Glory be to the Father ...
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THIRD DAY- Easter Sunday, April 12, 2020
Let us pray for all the faithfulChristians.
O most Merciful Jesus, who dost bestow Thy graces upon all in abundance from the treasure of Thy Mercy, receive all faithful Christians into the abode of Thy Most Merciful Heart and do not abandon them for all eternity. We beg this of Thee through the love that unites Thee to the Father and the Holy Ghost. The marvels of Mercy are unexplored, Nor sinner nor just can plumb it’s deep. God views us all with Mercy’s eye. And of His love would have us reap. Eternal Father, cast Thy Merciful Eye upon the souls of the faithful, who are the loving heritage of Thy Son, and through His sorrowful Passion grant them Thy blessings and encompass them with Thy unceasing care, that they may never lose their love and treasure of divine faith, but that they may glorify Thy boundless Mercy with the multitude of angels and saints for all eternity. Amen. Our Father ... Hail Mary ... Glory be to the Father ...