The Universal Catholic Church celebrates the Solemnity of the Immaculate Conception on 8 December. It is a holy day of obligation to attend Mass. This is the season we prepare for the birth of Jesus.
The Immaculate Conception refers to the conception of Mary, the mother of Jesus. The “immaculate” is not a reference to how she was conceived by her parents, Sts. Joachim and Anne. It acknowledges that God intervened and allowed her to be conceived without the stain of original sin.
Pope Pius IX proclaimed the Immaculate Conception a dogma in 1854. He explained: “‘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.'” (nos. 490-491. See also, nos. 721-726)
So why does the Church use the announcement of Jesus’ birth as the Gospel for this feast day? Before Gabriel tells Mary that she has been chosen to be the mother of Jesus, he greets her: “‘Hail, full of grace! The Lord is with you.’ But she was greatly troubled at what was said and pondered what sort of greeting this might be. Then the angel said to her, ‘Do not be afraid, Mary, for you have found favor with God.'” (Luke 1:28-30)
The Catechism of the Catholic Church explains the significance of this greeting. “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.”
The Immaculate Conception of Mary was part of God’s plan. According to Fr. Steve Grunow, “Christ, who receives his human flesh from his mother, receives this flesh from a person who, by a singular gift from God, herself comes into this world without original sin.”
“Christ saved her in an extraordinary way and gave her a holiness that she did not achieve for herself. He did this for her, for the sake of her mission — a mission that only she would bear,” he added. “The Immaculate Conception is not something easy, it is mysterious and miraculous, but is nevertheless a beautiful and extraordinary gift — a gift through which God in Christ acted to save his mother, and us from our sins …”