A heart that aches for love is apt to repeat itself and so it was with the Merciful Heart of Jesus.  On a number of occasions Jesus poured out His heart about the Feast of Mercy, which is now called Divine Mercy Sunday.  St. Faustina, at a loss about how to establish this feast in the Church, was at one point told that there is already such a feast.  When she mentioned this to the Lord, His response again is of a wounded lover.  This is how the conversation took place: 

"But, Jesus, I have one more word to say to You: I am very surprised that You bid me to talk about this Feast of Mercy, for they tell me that there is already such a feast and so why should I talk about it? And Jesus said to me, “And who knows anything about this feast? No one! Even those who should be proclaiming My mercy and teaching people about it often do not know about it themselves. That is why I want the image to be solemnly blessed on the first Sunday after Easter, and I want it to be venerated publicly so that every soul may know about it." (Diary, 341).

On April 30, 2000, St. John Paul II both canonized St. Faustina and mandated that the Universal Church celebrate this feast according to the wishes of the Merciful Lord.  Then on May 23, the Congregation for Divine Worship and the Discipline of the Sacraments stated that "throughout the world the Second Sunday of Easter will receive the name Divine Mercy Sunday, a perennial invitation to the Christian world to face, with confidence in divine benevolence, the difficulties and trials that mankind will experience in the years to come." 

Certainly, this day and its annual celebration is a consolation to the Merciful Heart of Jesus that is bursting with love for mankind.  Here are some excerpts from St Faustina's diary regarding the feast:

“I want the image solemnly blessed on the first Sunday after Easter, and I want it to be venerated publicly so that every soul may know about it.” (Diary, 341)

“This Feast emerged from the very depths of My mercy, and it is confirmed in the vast depths of my tender mercies.” (Diary, 420)

“On one occasion, I heard these words: “My daughter, tell the whole world about My Inconceivable mercy. I desire that the Feast of Mercy be a refuge and shelter for all souls, and especially for poor sinners. 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 fount of My mercy. The soul that will go to Confession and receive Holy Communion shall obtain complete forgiveness of sins and punishment. On that day all the divine floodgates through which grace flow are opened. Let no soul fear to draw near to Me, even though its sins be as scarlet. My mercy is so great that no mind, be it of man or of angel, will be able to fathom it throughout all eternity. Everything that exists has come forth from the very depths of My most tender mercy. Every soul in its relation to Me will contemplate My love and mercy throughout eternity. The Feast of Mercy emerged from My very depths of tenderness. It is My desire that it be solemnly celebrated on the first Sunday after Easter. Mankind will not have peace until it turns to the Fount of My Mercy.” (Diary, 699)

“I demand from you deeds of mercy, which are to arise out of love for Me. You are to show mercy to our neighbors always and everywhere. You must not shrink from this or try to excuse or absolve yourself from it... Yes, the first Sunday after Easter is the Feast of Mercy, but there must also be acts of mercy. ” (Diary, 742)

“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.” (Diary, 1109)