Solemnity of the Immaculate Conception

It is the clear and unanimous opinion of the Fathers that the most glorious Virgin, for whom "he who is mighty has done great things," was resplendent with such an abundance of heavenly gifts, with such a fullness of grace and with such innocence, that she is an unspeakable miracle of God—indeed, the crown of all miracles and truly the Mother of God; that she approaches as near to God himself as is possible for a created being; and that she is above all men and angels in glory. Hence, to demonstrate the original innocence and sanctity of the Mother of God, not only did they frequently compare her to Eve while yet a virgin, while yet innocence, while yet incorrupt, while not yet deceived by the deadly snares of the most treacherous serpent; but they have also exalted her above Eve with a wonderful variety of expressions. Eve listened to the serpent with lamentable consequences; she fell from original innocence and became his slave. The most Blessed Virgin, on the contrary, ever increased her original gift, and not only never lent an ear to the serpent, but by divinely given power she utterly destroyed the force and dominion of the evil one.

Let all the children of the Catholic Church, who are so very dear to us, hear these words of ours. With a still more ardent zeal for piety, religion and love, let them continue to venerate, invoke and pray to the most Blessed Virgin Mary, Mother of God, conceived without original sin. Let them fly with utter confidence to this most sweet Mother of mercy and grace in all dangers, difficulties, needs, doubts and fears. Under her guidance, under her patronage, under her kindness and protection, nothing is to be feared; nothing is hopeless. Because, while bearing toward us a truly motherly affection and having in her care the work of our salvation, she is solicitous about the whole human race. And since she has been appointed by God to be the Queen of heaven and earth, and is exalted above all the choirs of angels and saints, and even stands at the right hand of her only-begotten Son, Jesus Christ our Lord, she presents our petitions in a most efficacious manner. What she asks, she obtains. Her pleas can never be unheard.
—Pope Pius IX, Apostolic Constitution on the Immaculate Conception