Ave Maria Meditations
The Immaculate Conception of the Blessed Virgin Mary consists essentially in her exemption from original sin. From the first moment of her existence, her soul was adorned was sanctifying grace, which made her a beloved child of God. She was never in that state of separation from God in which all men find themselves before baptism. Mary was preserved from sin in view of the merits of her Son. The grace of the Redeemer prevented her from being tainted by original sin, whereas we have been rescued from this in through baptism.
The main reason which demanded the Immaculate Conception for Mary was her divine maternity. It was fitting that the Mother of God be always without sin, even original sin. The Son of God could create for Himself a Mother most pure; and He certainly has done so! His love for His Mother is infinitely greater than ours. If Mary had been conceived in sin, she would have been in a state of enmity toward her Son before He had chosen her as His Mother. Since He had come as Savior to redeem mankind, it was fitting that He redeem His Mother in a most excellent way than the rest of mankind, that is, by preserving her from sin, instead of only delivering her from it.
From the Complete Marian Prayerbook
