The Immaculate Conception CCC 490–493
490 To become the mother of the Savior, Mary “was enriched by God with gifts appropriate to such a role.”132 The angel Gabriel at the moment of the annunciation salutes her as “full of grace”.133 In fact, in order for Mary to be able to give the free assent of her faith to the announcement of her vocation, it was necessary that she be wholly borne by God’s grace.
491 Through the centuries the Church has become ever more aware that Mary, “full of grace” through God,134 was redeemed from the moment of her conception. That is what the dogma of the Immaculate Conception confesses, as Pope Pius IX proclaimed in 1854: The most Blessed Virgin Mary was, from the first moment of her conception, by a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Savior of the human race, preserved immune from all stain of original sin.135
492 The “splendor of an entirely unique holiness” by which Mary is “enriched from the first instant of her conception” comes wholly from Christ: she is “redeemed, in a more exalted fashion, by reason of the merits of her Son”.136 The Father blessed Mary more than any other created person “in Christ with every spiritual blessing in the heavenly places” and chose her “in Christ before the foundation of the world, to be holy and blameless before him in love”.137
493 The Fathers of the Eastern tradition call the Mother of God “the All-Holy” (Panagia), and celebrate her as “free from any stain of sin, as though fashioned by the Holy Spirit and formed as a new creature”.138 By the grace of God Mary remained free of every personal sin her whole life long.
Immaculate Conception (CCC 490-493, 508) Church Fathers What does this mean? There is a great deal of confusion about what this dogma actually means – a number of people (especially in the secular media) confuse the teaching of the Immaculate Conception with the virgin birth of Jesus Christ. But the dogma of Immaculate Conception has nothing directly to do with Jesus. Of course, Jesus was also immaculately conceived, but this is such a fundamental truth that the Church has never been forced to proclaim it in the face of denial. Very few Christians have ever suggested that Jesus sinned (a prominent example is Martin Luther, but he said this while drunk and so he might not have really meant it.)
What does the dogma mean? The best way to explain it is to quote the words of the dogma itself – on December 8, 1854, Pope Pius IX infallibly defined the dogma of the Immaculate Conception saying, “The Most Holy Virgin Mary was, in the first moment of her conception, by a unique gift of grace and privilege of Almighty God and in view of the merits of Jesus Christ the Redeemer of mankind, preserved free from all stain of original sin.” Simply stated, the Immaculate Conception is Mary’s conception without original sin, “Immaculate” meaning clean and pure without blemish. Mary from the moment she was conceived was without the consequences of original sin. She had sanctifying grace, and an uncorrupt nature. The Church also holds that Mary was never touched by personal sin (i.e. she never committed a sin in her life).