The Immaculate Conception is very often a source of confusion for Catholics and contention for non-Catholics. Though commonly misunderstood as referring to Christ’s conception in Mary, it actually refers to Mary’s own conception in her mother’s womb. From the moment of her conception, Mary was ‘by a singular grace and privilege granted by Almighty God… preserved free from all stain of original sin’ (Ineffabilis Deus, DS 2803), and by the grace of God ‘remained free of every personal sin for her whole life long’ (CCC 493). This is what we mean when we say that Mary was without sin.
Though this dogma is not explicitly revealed in Scripture, the angel Gabriel seemingly couldn’t be much clearer in his greeting to her as he announces that she is to become the mother of Christ our redeemer: ‘Hail, full of grace’ (Luke 1:28). If Mary is full of grace, there is no room for sin! It’s because of this lack of sin that she is truly free to be able to respond to God’s invitation with the willing ‘fiat’ that we read of in the subsequent lines of Scripture, because there was no sin to cloud her judgement (CCC 491). Just like us, whose human nature has been deprived of God’s supernatural grace because of original sin, Mary was in need of redemption through her son Jesus, but in a unique way was redeemed in advance, as it were, by being preserved from sin from the beginning, and enriched by a ‘gift of sublime grace’ for her role as Mother of God (Lumen Gentium, 53). In other words, she was saved from sin before sin could occur.
St Paul’s teaching that ‘the wages of sin are death’ literally means that sin separates us from God, in whom is the fullness of life. A woman living in this state of separation from God could not possibly conceive God Himself in her womb, and therefore we must conclude that the Mother of God had to be free from sin. Mary’s Immaculate Conception is necessary for our salvation because it is by the grace that preserved her from sin that she was able to conceive and bear Jesus, our Saviour, and so to share in His salvific mission on earth.
‘In the soul of this "daughter of Sion" there is manifested, in a sense, all the "glory of grace," that grace which "the Father...has given us in his beloved Son."’ (Redemptoris Mater, 8).
Though full of grace and blessed by God to a ‘special and exceptional degree’ (RM, 8), we mustn’t forget that Mary remained human like us! Mary holds out to us a perfect model of what we are all ultimately called to in Christ: a life without sin, and full of grace! She reveals to us the fullness of the grace that is available to us in Christ Jesus. She shows us what Jesus meant went He urged us to ‘be holy, because I am holy’ (1 Peter 1:16). In this way she inspires and challenges us to reach the heights of holiness which we were created for, knowing that we will inevitably fall – alas, we are not ‘full of grace’ – but should never tire of pressing on ‘toward the goal for the prize of the heavenly call of God in Christ Jesus’ (Phil. 3:14).