The Feast of the Immaculate Conception of Mary is celebrated on the 8th of December. It is believed that Mary was free of original sin from the moment of her conception, which kept her soul immaculate from birth.
This is one of the reasons we refer to her as ‘full of grace’, as the angel Gabriel had said to her “Hail, full of Grace, the Lord is with you.” People assume the Immaculate Conception refers to Jesus’ conception, but through the following references, we are able to understand that it is in fact about Mary herself.
“Chosen in advance to be the Mother of the Incarnate world, Mary is at the same time the first fruits of his redeeming action. The grace of Christ the Redeemer acted in her in anticipation, preserving her from original sin and from a contagion of guilt.” – Pope John Paul II, Dec 8 2003.
In view of her vocation to be the mother of the Holy One (Luke 1:35), we can affirm together that Christ’s redeeming work reached ‘back in Mary to the depths of her being, and to her earliest beginnings. This is not contrary to the teaching of Scripture, and can only be understood in the light of scripture. Roman Catholics can recognize in this what is affirmed by the dogma – namely ‘preserved from all stain of original sin’ and ‘from the first moment of her conception.’ – 2005 report by Anglican and Roman Catholic theologians.
As stated here, the doctrine of the Immaculate Conception places Our Lady before the faithful as an example of what God can do and what we can do, if like Mary, we put ourselves in God’s hands and at his service, always open to what God asks and always seeking to fulfill God’s will. The doctrine of the Immaculate Conception also encourages us to do our best to remain free from sin. Although we were all born with original sin and through the grace of Baptism are freed from sin, in the course of our life, because of human weakness, we fail to commit sin. The Immaculate Conception reminds us that if we cooperate with God’s grace as the Blessed Virgin Mary did, we can lead a life as free from sin as humanly possible.