The popularity of the Divine Mercy devotion is due to the fact of man’s sinfulness and our urgent need of obtaining God’s merciful action. This devotion has so much been strengthened by the writings of as compiled in her book: The Diary of Divine Mercy in my Soul.
The fact, we have to admit, is that first of all we are all sinners in need of God’s Mercy. It’s only the proud who may dare to say “I have no sin.” Yet we know from looking all around our world the evidence of man’s weakness, sinfulness and corruption. It’s only a hypocrite who pretends to be without fault or weakness.
Thus in paragraph 1541 of St. Faustina’s book we read the words of Jesus to her: “My daughter, encourage souls to say the chaplet which I have given to you. It pleases Me to grant everything they ask of Me by saying the chaplet. When hardened sinners say it, I will fill their souls with peace, and the hour of their death will be a happy one. Write this for the benefit of distressed souls: When a soul sees and realizes the gravity of its sins, when the whole abyss of the misery into which it immersed itself is displayed before its eyes, let it not despair, but with trust let it throw itself into the arms of My mercy, as a child into the arms of its beloved mother. These souls have a right of priority to My compassionate Heart, they have first access to My mercy.
Tell them that no soul that has called upon My mercy has been disappointed or put to shame. I delight particularly in a soul which has placed its trust in My goodness. Write that when they say this chaplet in the presence of the dying, I will stand between My Father and the dying person, not as the just Judge but as the merciful Savior.”