Mary, Mother of Mercy, occupied a very special place in the spirituality of Saint Faustina, who from childhood was very attached to Mary. When she became a nun in the Congregation of Our Lady of Mercy, her devotion to Mary grew even more. Sister Faustina was favored with several visions of Mary during which the holy Mother of God instructed her, helped her and assisted her in her prophetic mission of mercy, saying: “I am a Mother to you, through the unfathomable Mercy of God” (Notebooks, 449) and: “I am not only the Queen of Heaven, but also the Mother of Mercy and your Mother” (Notebook 330).
Sister Faustina venerated Mary especially as the Mother of the Son of God, who is Mercy incarnate, and Mother of all mankind. Mary taught Faustina to live in the presence of God in her soul, to love the Cross, and to practice the virtues that foster an attitude of trust in God and of mercy towards others. She revealed great mysteries to her.
Sister Faustina made this admission: “Suddenly I saw the Mother of God who said to me: Oh! How pleasing is the soul that faithfully follows the breath of grace; I gave the world the Savior, and you must speak to the world of his great Mercy and prepare the world for the second coming of Him who will come not as a merciful Savior, but as a just Judge. Oh, this day is terrible. The day of justice has been decided, the day of God’s wrath; the angels tremble before it. Speak to the souls of this great Mercy, as long as it is the time of Mercy; if you keep quiet now you will answer about this terrible day for many souls. Do not be afraid of anything, be faithful to the end; my heart suffers with yours…” (Notebooks 635).