Teresa Monaghen, of Pro Sanctity and Fr. John Sianchuck, C.Ss.R., a Ukranian Byzantine priest do a great job of explaining the Western and Eastern understanding of this great mystery.

Take a listen to the discussion posted above, that Bruce and I had with Teresa Monaghen, from Pro Sanctity and Fr. John Sianchuk, C.Ss.R., a Ukrainian Redemptorist priest discuss the difference and similarities of Western and Eastern understanding of the Immaculate  Conception of the Blessed Virgin Mary

[powerpress]

From the Catechism of the Catholic Church on the Immaculate Conception, 

“490 To become the mother of the Savior, Mary “was enriched by God with gifts appropriate to such a role.”¹³² The angel Gabriel at the moment of the annunciation salutes her as “full of grace”.¹³³ In fact, in order for Mary to be able to give the free assent of her faith to the announcement of her vocation, it was necessary that she be wholly borne by God’s grace.

491 Through the centuries the Church has become ever more aware that Mary, “full of grace” through God,¹³⁴ was redeemed from the moment of her conception. That is what the dogma of the Immaculate Conception confesses, as Pope Pius IX proclaimed in 1854:

The most Blessed Virgin Mary was, from the first moment of her conception, by a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Savior of the human race, preserved immune from all stain of original sin.¹³⁵

 492 The “splendor of an entirely unique holiness” by which Mary is “enriched from the first instant of her conception” comes wholly from Christ: she is “redeemed, in a more exalted fashion, by reason of the merits of her Son”.¹³⁶ The Father blessed Mary more than any other created person “in Christ with every spiritual blessing in the heavenly places” and chose her “in Christ before the foundation of the world, to be holy and blameless before him in love”.¹³⁷

493 The Fathers of the Eastern tradition call the Mother of God “the All-Holy” (Panagia), and celebrate her as “free from any stain of sin, as though fashioned by the Holy Spirit and formed as a new creature”.¹³⁸ By the grace of God Mary remained free of every personal sin her whole life long. ”