Ave Gratia Plena
This feast was established for the universal Church by Pope Pius IX when He proclaimed that from all eternity, the Triune Divinity chose the Blessed Virgin Mary to be the tabernacle of the Son of God. The Dogma of the Immaculate Conception proclaimed once and for all that it was unthinkable that Mary be defiled in any way by sin in any manner whatsoever. Thus, in that infinitesmal second that God created Mary He made her Immaculate. This grace, like all other graces since Adam and Eve's fall, was given to Mary through the merits of her Divine Son Jesus. She stood alone as one free of the stain of original sin, redeemed not from the evil already present at birth, but from any evil that threatened this sacred temple known as the Mother of God.