The Vatican website, in Pope Pius IX's Apostolic Constitution, Ineffabilis Deus, discusses the dogma of the Immaculate Conception, highlighting that Mary was preserved free from original sin. Ineffabilis Deus describes Mary as being "preserved free from all stain of original sin" from the moment of her conception.
The text also includes a section titled "Mary Compared with Eve," which emphasizes the comparison between Mary and Eve in their respective relationships with sin. This section explains that the Fathers of the Church often compared Mary to Eve, who was initially sinless, but then chose to disobey God.
Here's the key passage from Ineffabilis Deus regarding the comparison of Mary and Eve:
The document quotes early Church Fathers who compared Mary to Eve before her fall from grace, emphasizing Mary's original innocence and sanctity. It states that unlike Eve, who was deceived and became a slave to sin, Mary never gave in to temptation and, through divine power, overcame the influence of the evil one. The document further explains that because of her freedom from all sin and her victory over Satan, Mary is seen as being more glorious than Eve. The idea of Mary as the "New Eve" is a significant concept in Catholic theology, representing her role in reversing the consequences of Eve's disobedience through her own perfect obedience to God
Text of Ineffabilis Deus
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.
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She is celebrated as innocence never sullied and as the second Eve who brought forth the Emmanuel.