Apostolic Constitution of Pope Pius IX solemnly defining the dogma of the Immaulate Conception, 8 December 1854.
God Ineffable--whose ways are mercy and truth, whose will is omnipotence itself, and whose wisdom "reaches from end to end mightily, and orders all things sweetly"--having foreseen from all eternity the lamentable wretchedness of the entire human race which would result from the sin of Adam, decreed, by a plan hidden from the centuries, to complete the first work of his goodness by a mystery yet more wondrously sublime through the Incarnation of the Word. This he decreed in order that man who, contrary to the plan of Divine Mercy had been led into sin by the cunning malice of Satan, should not perish; and in order that what had been lost in the first Adam would be gloriously restored in the Second Adam. From the very beginning, and before time began, the eternal Father chose and prepared for his only-begotten Son a Mother in whom the Son of God would become incarnate and from whom, in the blessed fullness of time, he would be born into this world. Above all creatures did God so lover her that truly in her was the Father well pleased with singular delight. Therefore, far above all the angels and all the saints so wondrously did God endow her with the abundance of all heavenly gifts poured from the treasury of his divinity that this mother, ever absolutely free of all stain of sin, all fair and perfect, would possess that fullness of holy innocence and sanctity than which, under God, one cannot even imagine anything greater, and which, outside of God, no mind can succeed in comprehending fully.
And indeed it was wholly fitting that so wonderful a mother should be ever resplendent with the glory of most sublime holiness and so completely free from all taint of original sin that she would triumph utterly over the ancient serpent. To her did the Father will to give his only-begotten Son--the Son whom, equal to the Father and begotten by him, the Father loves from his heart--and to give this Son in such a way that he would be the one and the same common Son of God the Father and of the Blessed Virgin Mary. It was she whom the Son himself chose to make his Mother and it was from her that the Holy Spirit willed and brought it about that he should be conceived and born from whom he himself proceeds.
And indeed, illustrious documents of venerable antiquity, of both the Eastern and the Western Church, very forcibly testify that this doctrine of the Immaculate Conception of the most Blessed Virgin, which was daily more and more splendidly explained, stated and confirmed by the highest authority, teaching, zeal, knowledge, and wisdom of the Church, and which was disseminated among all peoples and nations of the Catholic world in a marvelous manner--this doctrine always existed in the Church as a doctrine that has been received from our ancestors, and that has been stamped with the character of revealed doctrine. For the Church of Christ, watchful guardian that she is, and defender of the dogmas deposited with her, never changes anything, never diminishes anything, never adds anything to them; but with all diligence she treats the ancient documents faithfully and wisely; if they really are of ancient origin and if the faith of the Fathers has transmitted them, she strives to investigate and explain them in such a way that the ancient dogmas of heavenly doctrine will be made evident and clear, but will retain their full, integral, and proper nature, and will grown only within their own genus--that is, within the same dogma, in the same sense and the same meaning.
Hence, 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.
As if these splendid eulogies and tributes were not sufficient, the Fathers proclaimed with particular and definite statements that when one treats of sin, the holy Virgin Mary is not even to be mentioned; for to her more grace was given than was necessary to conquer sin completely. They also declared that the most glorious Virgin was Reparatrix of the first parents, the giver of life to posterity; that she was chosen before the ages, prepared for himself by the Most High, foretold by God when he said to the serpent, "I will put enmities between you and the woman"--unmistakable evidence that she was to crush the poisonous head of the serpent. And hence they affirmed that the Blessed Virgin was, through grace, entirely free from every stain of sin, and from all corruption of body, soul and mind; that she was always united with God and joined to him by an eternal covenant; that she was never in darkness but always in light; and that, therefore, she was entirely a fit habitation for Christ, not because of the state of her body, but because of her original grace.
Therefore, having full trust in the Lord that the opportune time had come for defining the Immaculate Conception of the Blessed Virgin Mary, Mother of God, which Holy Scripture, venerable Tradition, the constant mind of the Church, the desire of Catholic bishops and the faithful, and the memorable Acts and Constitutions of our predecessors, wonderfully illustrate and proclaim, and having most diligently considered all things, as we poured forth to God ceaseless and fervent prayers, we concluded that we should no longer delay in decreeing and defining by our supreme authority the Immaculate Conception of the Blessed Virgin. And thus, we can satisfy the most holy desire of the Catholic world as well as our own devotion toward the most holy Virgin, and at the same time honor more and more the only begotten Son, Jesus Christ our Lord through his holy Mother--since whatever honor and praise are bestowed on the Mother redound to the Son.
Wherefore, in humility and fasting, we unceasingly offered our private prayers as well as the public prayers of the Church to God the Father through his Son, that he would deign to direct and strengthen our mind by the power of the Holy Spirit. In like manner did we implore the help of the entire heavenly host as we ardently invoked the Paraclete. Accordingly, by the inspiration of the Holy Spirit, for the honor of the Holy and undivided Trinity, for the glory and adornment of the Virgin Mother of God, for the exaltation of the Catholic Faith, and for the furtherance of the Catholic religion, by the authority of Jesus Christ our Lord, of the Blessed Apostles Peter and Paul, and by our own: "We declare, pronounce, and define that the doctrine which holds that the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved free from all stain of original sin, is a doctrine revealed by God and therefore to be believed firmly and constantly by all the faithful."
Hence, if anyone shall dare--which God forbid!--to think otherwise than as has been defined by us, let him know and understand that he is condemned by his own judgment; that he has suffered shipwreck in the faith; that he has separated from the unity of the Church; and that, furthermore, by his own action he incurs the penalties established by law if he should dare to express in words or writing or by any other outward means the errors he think in his heart.
1. Et quidem decebat omnino, ut perfectissimae sanctitatis splendoribus semper ornata fulgeret, ac vel ab ipsa originalis culpae labe plane immunis amplissimum de antiquo sepente triumphum referret tam venerabilis mater, cui Deus Pater unicum Filius suum, quem de corde suo aequalem sibi genitum tamquam seipsum diligit, ita dare disposuit, ut naturaliter esset unus idemque communis Dei Patris et Virginis Filius, et quam ipse Filius, Filius substantialiter facere sibi matrem elegit, et de qua Siritus Sanctus voluit et operatus est, ut conciperetur et nasceretur ille, de quo ipse procedit.
2. Cf. St. Augustine: De Natura et Gratia, c. 36.
25. Gn 3:15.
29. Declaramus, pronuntiamus et definimus doctrinam quae tenet beatissimam Virginem Mariam in primo instanti suae conceptionis fuisse singulari Omnipotentis Dei gratia et privilegio, intuitu meritorum Christi Jesu Salvatoris humani generis, ab omni originalis culpae labe praeservatam immunem, esse a Deo revelatam, atque idcirco ab omnibus fidelibus firmiter constanterque credendam. Cf. Denz., n. 1641.
Excerpted from Pius IX's Apostolic Constitution solemnly defining the Immaculate Conception, Ineffabilis Deus, 8 December 1854.