The Feast of the Immaculate Conception

Today the Church observes a most solemn feast, the immaculate conception of Mary. God saw to it that she would not be stained (macula) with original sin because of her crucial role in salvation history. Just as the Ark of the Covenant in the Old Testament could not be touched by human hands (ie. sin) the ark of the New Covenant would not carry the stain of original sin.
God chose to use the grace obtained for her by her very own child's death on the cross and apply it to her at the moment of conception to redeem her.

• How did God apply Jesus saving grace to Mary at her conception, when her son wouldn't die on the cross for another 33 years?  God can do anything and he is not limited by our linear conception of time.

•  Did Mary need to be without sin? No, but the Church felt it was "fitting."

The Catechism states:


490 To become the mother of the Saviour, Mary “was enriched by God with gifts appropriate to such a role.” The angel Gabriel at the moment of the annunciation salutes her as “full of grace”.  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, 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, Saviour of the human race, preserved immune from all stain of original sin. 

• Does this mean Mary is divine and to be worshiped?  No, only God is to be worshiped but it teaches us something about Christ and his divinity as well as gives us hope that someday we too will be full of grace and sinlessly perfect before God, as she is. There must be something very important about Jesus, that God would see fitting that he come into the world through a sinless virgin's fiat.