If the soul of the Blessed Virgin had never incurred the stain of original sin, this would be derogatory to the dignity of Christ, by reason of His being the universal Saviour of all. Consequently after Christ, who, as the universal Saviour of all, needed not to be saved, the purity of the Blessed Virgin holds the highest place. For Christ did not contract original sin in any way whatever, but was holy in His very Conception, according to Luke 1:35: “The Holy which shall be born of thee, shall be called the Son of God.” But the Blessed Virgin did indeed contract original sin, but was cleansed therefrom before her birth from the womb. This is what is signified (Job 3:9) where it is written of the night of original sin: “Let it expect light,” i.e. Christ, “and not see it”–(because “no defiled thing cometh into her,” as is written in Wisdom 7:25), “nor the rising of the dawning of the day,” that is of the Blessed Virgin, who in her birth was immune from original sin. (Summa Theologica, III, Q.27, A.2, ad 2)