December 8th is the Feast of the Immaculate Conception in which the Church celebrates the dogma which states that the Blessed Virgin Mary was preserved, in the first instant of her conception, by a singular grace and privilege of God Omnipotent and because of the merits of Jesus Christ the Saviour of the human race, free from all stain of original sin.
The Blessed Virgin Mary is the Ark of the Covenant and was to be the dwelling place of the Word made Flesh, True God and true Man, and could, as a consequence, have no divine hatred or malediction, no stain on the soul, could never be in a state of non-justice or spiritual death, or under the subject of the empire of Satan, or subject to the law of concupiscence, or under the penalty of the common sin.
These effects presuppose the loss of the sanctifying grace, but the Blessed Virgin Mary is God's most perfect creation and is loved more by Him than all the saints and angels combined.
In the Bull, Ineffabilis Deus, Pope Pius IX states: "From the very beginning, and before time began, the eternal Father chose and prepared for his only-begotten Son a Mother in whom the Son of God would become incarnate and from whom, in the blessed fullness of time, he would be born into this world. Above all creatures did God so loved her that truly in her was the Father well pleased with singular delight. Therefore, far above all the angels and all the saints so wondrously did God endow her with the abundance of all heavenly gifts poured from the treasury of his divinity that this mother, ever absolutely free of all stain of sin, all fair and perfect, would possess that fullness of holy innocence and sanctity than which, under God, one cannot even imagine anything greater, and which, outside of God, no mind can succeed in comprehending fully."
Ora pro nobis, sancta Dei Genetrix!