I desire that the first Sunday after Easter be the Feast of Mercy - the Lord Jesus said to Sr. Faustina. In the following years, Jesus returned to this demand in as many as 14 different apparitions, establishing very clearly the location of this Feast in the Church's liturgical calendar, and defining the reason and objective of its institution, the manner in which preparations for it and the celebration itself were to be conducted.

Jesus explained why he wanted this Feast instituted: Souls perish in spite of My bitter passion ...I am giving them the last hope of salvation that is, the Feast of Mercy. If they will not adore My mercy, they will perish for eternity. The Feast is to be a day of special worship of God in the mystery of His mercy which is the source and motive of all His acts toward man, and particularly of the act of redemption. In accordance with God's will, it is also a day of special grace for all souls, and particularly for sinners who are most in need of God's mercy. The Feast of My Mercy - Jesus said - has issued forth from My very depths for the consolation of the whole world.

It is with this very day, and more precisely, with the Holy Communion received on this day after making a good confession, that the greatest of the Lord's promises is connected. We are referring here to the promise of complete remission of sins and punishment. Yet this grace is much more than just a plenary indulgence. A plenary indulgence entails merely the remission of temporal punishment, for sins committed, but it never amounts to the remission of the sins themselves. This grace is basically also greater than the grace of the six Sacraments, other than Baptism, since the remission of sins and punishment is the sacramental grace only of Holy Baptism. Whereas in the above promises, Jesus has attributed the power to remit sins and punishment to the Holy Communion received on the Feast of Mercy (...) Obviously, the Holy Communion must be received on this day not only in a state of grace, but all other basic conditions of the devotion to the Divine Mercy must be observed.

The Lord Jesus did not limit His generosity to this single though so exceptional a grace, but promised to pour out a whole ocean of graces upon those souls who approach the fount of His mercy, as on that day all the divine floodgates through which graces flow are open. The greatness of this Feast consists among others in the fact that all people, even those who have only become converted on that day, may partake of all the graces Jesus has prepared for this Feast. The graces and benefits may be received by both the individuals and whole communities, providing they ask for them in a spirit of great trust.

The preparation for this feast is to be a novena consisting of the recitation of the Divine Mercy Chaplet for nine days, beginning on Good Friday. Sr. Faustina's Diary also contains an example of a novena which Jesus dictated for her personal use indicating for whom she should pray. All Christians may likewise make this novena with fervor and piety. Whereas the novena consisting of the chaplet to the Divine Mercy should be looked upon as the most appropriate preparation to the Feast, in accordance with the wish of the Lord Jesus. The Feast as Jesus conceived of it holds forth the promise of every possible grace.

As regards the manner in which the Feast is to be celebrated, Jesus wished that on that day the image of Mercy begiven public veneration. He also wished that the priests should tell souls of the great and unfathomable mercy of God; the faithful should practice acts of mercy toward their neighbors and they should receive with trust the Sacrament of Reconciliation and the Holy Eucharist.

The Divine Mercy had been worshipped spontaneously on the first Sunday after Easter already during the II World War. Officially, the Feast had first been instituted in the Cracow diocese by Franciszek Cardinal Macharski in his annual Pastoral Letter for Lent in the year 1985. In the subsequent years, the bishops of other Polish dioceses followed his example. In the year 1995 at the specific request of the Polish Episcopate, the Holy See issued a decree which permitted the celebration of this Feast in all Polish dioceses, provided the liturgical order for this day is preserved.