“I protect souls that spread the worship of My Mercy throughout their lives, as a loving mother protects her baby; and at the hour of their death I shall not be a Judge unto them, but their merciful Saviour” (Diary 1075). This is what the Lord Jesus promised to everyone who will proclaim His Mercy, spread its honour in any way. Priests can rejoice at His additional promise: “Hardened sinners will experience contrition and repent at their words when they preach on My infinite mercy, on the compassion I have in My heart for sinners. I shall endow those priests who preach and glorify My mercy with a singular power, I shall invest their words with special authority, and I shall move the hearts of those to whom they preach” (Diary 1521). These promises show how important it is to spread the honour of the Divine Mercy since Jesus promises His maternal care, during the lifetime and at the hour of death, to everyone who will undertake this task. Therefore, apart from the Image, Feast, Chaplet and Hour of Mercy, spreading honour of the Divine Mercy is also a form of the Devotion, because Jesus also attached promises to it and the promises pertain to all people.
Spreading honour of the Mercy, that is, proclaiming the mystery of the Divine Mercy, most fully revealed in the crucified and risen Christ, by the testimony of life, deeds, words and prayer is not only to show the road to a beautiful and happy life on earth but also, and maybe first of all, it is to serve the work of salvation and sanctification of the world as well as it is to prepare humanity for Christ’s second coming to earth: The Lord Jesus said to Sister Faustina: “Secretary of My mercy, write of this, and tell souls about My great mercy, for the terrible day, the day of My justice is close at hand” (Diary 965). “Do not stop preaching My mercy” (Diary 1521). “Tell the whole world of My unfathomable mercy” (Diary 699). “Let all mankind learn of My unfathomable mercy. It is the sign for the end times; after that will come the day of justice” (Diary 848). “Write this down: Before I come as the just Judge, I shall first fling wide open the door of My mercy. Whoever does not want to pass through the door of My mercy must pass through the door of My justice…” (Diary 1146). Therefore, the Lord Jesus’ urgent call directed to Sister Faustina and, through her, to the entire Church and the whole world, can be found so many times in the 'Diary’.
The task of preaching the message of Mercy arises from the gift recei- ved as early as during the Sacrament of Holy Baptism. It is also a right and duty of the Church and, thus, of all the faithful. In 2002 Holy Father John Paul II said in Błonia Park in Cracow: „The hour has come when the message of Divine Mercy is able to fill hearts with hope and to become the spark of a new civilization: the civilization of love”.