The Immaculate Conception of the Blessed Virgin Mary is one of the dogmas of the Church. It was declared a dogma by Pope Pius IX on 8 December 1854. In declaring this dogma, the pope stated, "that the Blessed Virgin Mary, in the first instance of her conception, by the singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Saviour of the human race, was preserved free from all stain of original sin..."

Some early Church fathers contrasted the obedience of Mary with the disobedience of Eve. Eve's disobedience caused the loss of the original holiness that God had intended for every man and woman and the loss of original harmony between humanity and the world.

Original sin is a result of this loss of original holiness and harmony. While Eve's disobedience caused death, Mary's obedience brought life through the Person of her Son, Jesus. As St. Irenaeus wrote, "Eve's disobedience was loosed by the obedience of Mary."

However, the dogma makes it clear that Mary's preservation from original sin is not due to her own efforts but the result of the merits of her Son, Jesus.

In his letter to the Ephesians, Paul writes that God had meant, from before the world was created, that we are holy and spotless. But sin and death entered the world because of the disobedience of Adam and Eve, however, original holiness intended for the human race was restored by Jesus.