The most holy Virgin Mary was, in the first moment of her conception, by a unique gift of grace and privilege of almighty God, in view of the merits of Jesus Christ the Redeemer of mankind, preserved free from all stain of original sin. {Formal Definition of Pope Pius IX, 1854} God chose and prepared Mary to be his mother. Jesus could not be born of sin. He is not a descendant of Original Sin. Jesus was nourished in Mary‘s womb. Her mother‘s milk nursed Him. Would God the Father let anything impure enter Jesus‘ body? If we believe that Jesus saves us from sin and death even after we have committed our own personal sins, why should we balk at the idea that He saved the woman He chose to be His Mother from sin and death even before she was born? Her immaculate conception was brought about by the grace flowing from the Cross, not from anything she did on her own. Mary is in NO WAY a Savior. She IS, however, the Mother of the Savior, and as such needed to be as pure as possible. Hail Mary, full of grace…… (Luke 1:28) Mary had to be sinless in order to be in such close proximity to God Himself. The whole Bible teaches this (e.g., Ex 3:5; Deut 23:14). God's Presence imparts and requires holiness (1 Cor 3:13-17; 1 Jn 3:3-9). The Jewish high priest entered the Holy of Holies (where the Ark and God's Special Presence were) only once a year, under threat of death if God's instructions were violated (Lev 16:2-4,13). The Ark itself was so holy that only a few were allowed to touch it (Num 4:15; 2 Sam 6:2-7). Thus, Mary, due to her ineffable physical and spiritual relationship with God the Son, the Holy Spirit (as "Spouse"), and God the Father (as "Daughter of Zion"), necessarily had to be granted the grace of sinlessness from conception, just as we all will be cleansed utterly in order to be present with God in heaven (Rev 21:27). Seen in this light, the Immaculate Conception, though still technically a deduction from the Bible, is a very biblical doctrine indeed. *Full of Grace (LUK 1:28). *CCC 490 - 493.

*Full of Grace (LUK 1:28).
*CCC 490 - 493.