The most recent practical link to the Sacred Heart of Jesus and the devotional icon of the Lord's Merciful love came from the Polish nun Saint Faustina Kowalska.
Jesus appeared to her on February 22, 1931, with His right hand bestowing blessings and His left hand pointing towards His Sacred Heart, which emitted two rays: one pale; the other a bright red. These rays represent the Water and Blood that came out of Jesus' pierced side while on the Cross.
This symbolizes the purifying virtues of Baptism and Confession and the regenerative virtue of the Holy Eucharist.
Jesus to St. Faustina: "My daughter, write these words and speak to souls. All the blood and all the tears of the world wide adore my Mercy and infuse the dying souls will bring peace and will relieve those who trust in my Mercy and will give them strength in their last hour; they will will give up their fear of death and will face everything they ask for."
Saint Faustina said: "During Holy Mass when Jesus was exposed through the Holy Sacrament before Holy Mass, I saw a great deal of light coming out of the Holy Host, one very pale and the other a bright red light, just as it is depicted in this image."
First recite the Our Father, Hail Mary and the Apostles' Creed.
Then on the Our Father bead, say the following words: "Eternal God, in whose mercy lives the whole of creation and eternity of Your dearly beloved Son, Our Lord Jesus Christ, is appeased in us and shed of his precious Blood."
Let's report the words of Jesus to St. Faustina: "I desire that this image be venerated by the entire world. I promise that the souls of those who will venerate this image will not perish. I even promise victory over their enemies, already here on earth, but especially at the hour of death.
I will defend that soul in the name of glory." Jesus, Himself explained the significance of this devotion: "My daughter, tell all that I am love and mercy personified. The wound in my Heart signifies the unlimited living waters of Mercy.
Tell all the souls that I protect them with my shield of Mercy; it is for them that I fight against the just umbrage of my Father [...] My daughter," He'll suffering of humanity to secure itself by his Mercy of my Heart and I will fill them with peace [...] Souls are perishing, regardless of my sorrowful Passion.
I concede to them the last table of salvation, meaning my merciful feast [...] this oven is a sign of the end days; after such, the day of judgment is upon you."
After showing His Infinite Mercy, the Lord also showed St. Faustina "hell". "Today, under the guide of an angel, I went into the abyss of hell. It is a place of extreme torments in the entire, huge, terrifying surroundings.
These are the various tortures and torments that I have seen: First torture: This consists of hell as being the loss of the Presence of God; Second: the torturous remorseful conscience; Third: the knowledge that such a destiny will never change; Fourth: this torture is a pain that penetrates the soul, but does not nullify it; it is a terrible torture and it is a purely spiritual, living fire lit only by God's wrath.
Fifth: This is the torture of eternal darkness, a horrible suffocating, putrid odor; even if it is dark, the demons and the condemned souls can see each other among themselves and see all the evil that others have done as well as their own evil.
Sixth: This torture is the knowledge of having Satan as a constant companion. Seventh and last: This torture is the incomparable degradation of God's wrath, in blasphemy, cursing and swearing. The sinner should realize the same ways that he sins is the way he is going to suffer for all eternity.
I am writing this by the Lord's direction, so that no one can say that there is no hell, or that no one ever been there or that no one knows how it is.
I, Sister Faustina, under the Lord's direction, have been in the abyss of hell, for the simple reason of being able to tell everyone and to witness that hell does exist. What I have written is only a weak shadow of what I have actually seen."