𝗘𝗜𝗚𝗛𝗧 𝗠𝗔𝗝𝗢𝗥 𝗥𝗘𝗔𝗦𝗢𝗡𝗦 𝗧𝗢 𝗥𝗘𝗝𝗘𝗖𝗧 𝗞𝗢𝗪𝗔𝗟𝗦𝗞𝗔'𝗦 "𝗗𝗜𝗩𝗜𝗡𝗘 𝗠𝗘𝗥𝗖𝗬"
I. PROHIBITED. The first and sufficient reason to reject Sister Faustina Kowalska's "divine mercy" revelation and devotion, is the authority of Pope Pius XII, Pope John XXIII, and the Sacred Congregation who 𝗰𝗼𝗻𝗱𝗲𝗺𝗻𝗲𝗱 𝗶𝘁 — 𝗻𝗼𝘁 𝗼𝗻𝗰𝗲, 𝗻𝗼𝘁 𝘁𝘄𝗶𝗰𝗲, 𝗯𝘂𝘁 𝘁𝗵𝗿𝗶𝗰𝗲, i.a. the most notable is the decree of November 19, 1958 (Cardinal Ottaviani, Plenary Meeting of the Divine Office):
“1. The supernatural nature of the revelations made to Sr. Faustina is 𝗻𝗼𝘁 𝗲𝘃𝗶𝗱𝗲𝗻𝘁.
“2. 𝗡𝗼 𝗳𝗲𝗮𝘀𝘁 of Divine Mercy is to be instituted.
“3. It is 𝗳𝗼𝗿𝗯𝗶𝗱𝗱𝗲𝗻 𝘁𝗼 𝗱𝗶𝘃𝘂𝗹𝗴𝗲 𝗶𝗺𝗮𝗴𝗲𝘀 𝗮𝗻𝗱 𝘄𝗿𝗶𝘁𝗶𝗻𝗴𝘀 that propagate this devotion under the form received by Sr. Faustina.”
The force of such authority ought to compel an obedient Catholic to submit, or at least to understand that there is no supernatural character in the alleged revelations on which the form of devotion is founded.
But if this does not suffice for you, proceed to the other reasons, especially the very cause.
II. HERETICAL. Pope Leo XIII once said that a single drop of heresy poisons the whole faith, no matter how beautiful are its other aspects; and the Roman Catechism and the Church Fathers teach that a single formal heresy suffices for a Catholic to lose his entire faith and become a heretic. Now one of the most dangerous elements in Sister Faustina's diary is 𝘁𝗵𝗲 𝗮𝗽𝗽𝗮𝗿𝗶𝘁𝗶𝗼𝗻'𝘀 𝗵𝗲𝗿𝗲𝘁𝗶𝗰𝗮𝗹 𝗳𝗹𝗮𝘁𝘁𝗲𝗿𝘆 𝘁𝗼 𝗵𝗲𝗿, 𝗷𝘂𝘀𝘁 𝗮𝘀 𝘁𝗵𝗲 𝗱𝗲𝘃𝗶𝗹 𝗶𝗻 𝘁𝗵𝗲 𝗳𝗼𝗿𝗺 𝗼𝗳 𝗮 𝘀𝗲𝗿𝗽𝗲𝗻𝘁 𝗱𝗲𝗰𝗲𝗶𝘃𝗲𝗱 𝘁𝗵𝗲 𝗳𝗶𝗿𝘀𝘁 𝘄𝗼𝗺𝗮𝗻 𝗯𝘆 𝗳𝗹𝗮𝘁𝘁𝗲𝗿𝘆, by saying that she and her husband will be "as Gods knowing good and evil" (Genesis 3:4,5). The apparition, who alleged himself as Christ, claims to unite with her "𝘮𝘰𝘳𝘦 𝘪𝘯𝘵𝘪𝘮𝘢𝘵𝘦𝘭𝘺 𝘢𝘴 𝘸𝘪𝘵𝘩 𝘯𝘰 𝘰𝘵𝘩𝘦𝘳 𝘤𝘳𝘦𝘢𝘵𝘶𝘳𝘦" (Diary, no. 707, apparition of October 2, 1936), and describes her love as "𝘴𝘰 𝘱𝘶𝘳𝘦, 𝘱𝘶𝘳𝘦𝘳 𝘵𝘩𝘢𝘯 𝘵𝘩𝘢𝘵 𝘰𝘧 𝘵𝘩𝘦 𝘢𝘯𝘨𝘦𝘭𝘴" (ibid., no. 1061, apparition of May 23, 1937). Both of these are 𝗱𝗲𝗿𝗼𝗴𝗮𝘁𝗼𝗿𝘆 𝘁𝗼 𝘁𝗵𝗲 𝗩𝗶𝗿𝗴𝗶𝗻 𝗠𝗮𝗿𝘆, "𝗺𝗼𝘀𝘁 𝗯𝗹𝗲𝘀𝘀𝗲𝗱 𝗮𝗺𝗼𝗻𝗴 𝘄𝗼𝗺𝗲𝗻" (𝗟𝘂𝗸𝗲 𝟭:𝟮𝟴,𝟰𝟮), who alone was most intimately united with God, above all creatures and next to the Son of God, by reason of her "singular privilege and gift of grace" of the Immaculate Conception (Ineffabilis Deus, ex cathedra) and of her relation as the Mother of God. This certainly leads Sister Faustina not only to heresy, but also to vanity, which is unbecoming for a holy religious.
III. SACRILEGIOUS. Kowalska said in her diary, "One day Jesus said to me, 'I am going to leave this house [church].... Because there are things here which displease me.' And 𝘵𝘩𝘦 𝘏𝘰𝘴𝘵 𝘤𝘢𝘮𝘦 𝘰𝘶𝘵 𝘰𝘧 𝘵𝘩𝘦 𝘵𝘢𝘣𝘦𝘳𝘯𝘢𝘤𝘭𝘦 𝘢𝘯𝘥 𝘤𝘢𝘮𝘦 𝘵𝘰 𝘳𝘦𝘴𝘵 𝘪𝘯 𝘮𝘺 𝘩𝘢𝘯𝘥𝘴 𝘢𝘯𝘥 𝘐, 𝘸𝘪𝘵𝘩 𝘫𝘰𝘺, 𝘱𝘭𝘢𝘤𝘦𝘥 𝘪𝘵 𝘣𝘢𝘤𝘬 𝘪𝘯 𝘵𝘩𝘦 𝘵𝘢𝘣𝘦𝘳𝘯𝘢𝘤𝘭𝘦. 𝘛𝘩𝘪𝘴 𝘸𝘢𝘴 𝘳𝘦𝘱𝘦𝘢𝘵𝘦𝘥 𝘢 𝘴𝘦𝘤𝘰𝘯𝘥 𝘵𝘪𝘮𝘦, 𝘢𝘯𝘥 𝘐 𝘥𝘪𝘥 𝘵𝘩𝘦 𝘴𝘢𝘮𝘦 𝘵𝘩𝘪𝘯𝘨. 𝘋𝘦𝘴𝘱𝘪𝘵𝘦 𝘵𝘩𝘪𝘴, 𝘪𝘵 𝘩𝘢𝘱𝘱𝘦𝘯𝘦𝘥 𝘢 𝘵𝘩𝘪𝘳𝘥 𝘵𝘪𝘮𝘦.” (Diary, no. 44). On the contrary, St. Thomas Aquinas teaches (Summa Theologica, III.82.3) that “out of reverence towards this sacrament, nothing touches it, but what is consecrated; hence the corporal and the chalice are consecrated, and likewise the priest’s hands, for touching this sacrament. Hence 𝗶𝘁 𝗶𝘀 𝗻𝗼𝘁 𝗹𝗮𝘄𝗳𝘂𝗹 𝗳𝗼𝗿 𝗮𝗻𝘆𝗼𝗻𝗲 𝗲𝗹𝘀𝗲 𝘁𝗼 𝘁𝗼𝘂𝗰𝗵 𝗶𝘁 𝗲𝘅𝗰𝗲𝗽𝘁 𝗳𝗿𝗼𝗺 𝗻𝗲𝗰𝗲𝘀𝘀𝗶𝘁𝘆, for instance, if it were to fall upon the ground, or else in some other case of urgency.” Now since Sister Faustina is neither a man nor a priest, her unconsecrated hands are not worthy to hold the Most Blessed Sacrament.
