Why do we celebrate the Immaculate Conception?

We celebrate the Solemnity of the Immaculate Conception, a Holy Day of Obligation, on December 8.

In 1854, Pope Pius IX declared the dogma of the Immaculate Conception:

The Most Holy Virgin Mary was, in the very 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.” (Ineffabilis Deus, Apostolic Constitution of Pope Pius IX on the Immaculate Conception)

Thus, the Church teaches that the Blessed Mother was redeemed by Her Son, just as we are, but by a Divine anticipation of the merits of the Word-made-flesh. Like Eve before her, she was not subject to the Fall and thus to the prince of this world. However, unlike Eve, she would never surrender that freedom which God’s grace provided her.

What is the difference between the Immaculate Conception and the Virgin Birth?

The Immaculate Conception indicates that Our Lady was preserved from the penalty of original sin from the moment of her conception. The Virgin Birth means that Jesus was conceived and born, not of man, but by the Holy Spirit.

How do we know Mary was Immaculately Conceived?

The Church teaches us that Mary was immaculately conceived. The Catechism of the Catholic Church states,

To become the mother of the Savior, Mary "was enriched by God with gifts appropriate to such a role." The angel Gabriel at the moment of the annunciation salutes her as "full of grace." 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.

Through the centuries the Church has become ever more aware that Mary, "full of grace" through God, 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.” (CCC 490-491)

How are the Immaculate Conception, Lourdes and St. Bernadette related?

In 1858, just four years after Pope Pius IX proclaimed the dogma of the Immaculate Conception, Our Lady appeared on 18 occasions to 14-year-old Bernadette Soubirous in Lourdes, France. In one of the last apparitions, that of March 25, the feast of the Annunciation and Incarnation, the Virgin revealed her name, saying, "Que soy era Immaculada Counceptiou,” which means “I am the Immaculate Conception” in the dialect of the region.

The beautiful story of the events is told in the classic film The Song of Bernadette, based on a 1941 book by the Jewish writer Franz Werfel. Werfel found refuge from the Nazis in Lourdes for 5 weeks, during which time he promised to tell the story of Bernadette if he was able to get to America, which he did.

Who is the Immaculate Conception and why?

Mary, the Mother of God, is the Immaculate Conception. This is because she was chosen by God and given the grace of being preserved from original sin.

Pope St. John Paul II said,

Man looks on the outward appearance, but the Lord looks on the heart” (1 Sm 16:7). And Mary’s heart was fully disposed to the fulfilment of the divine will. This is why the Blessed Virgin is the model of Christian expectation and hope... In her heart there is no shade of selfishness: she desires nothing for herself except God’s glory and human salvation. For her, the very privilege of being preserved from original sin is not a reason to boast, but one for total service to her Son’s redemptive mission.
 

Why did God choose Mary?

The Catechism of the Catholic Church (paragraphs 492-493) teaches,

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." 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.”

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." By the grace of God Mary remained free of every personal sin her whole life long.

From EWTN