Today is the Feast of the Immaculate Conception and so I believe it is worth it to talk about how the sinlessness of Mary is Biblical. While the doctrine of the Immaculate Conception is not explicitly outlined in the Bible, many hints and shadows of this inspired teaching can be found in the Old and New Testaments. If we do not accept the Apostolic authority of the Church's bishops, we may not find these Biblical passages to be sufficient, but it should at least be clear that the Immaculate Conception is consistent with the Scriptures. Protestants usually bring out this passage on men’s sinfulness, “there is no man on earth so just as to do good and never sin”(Ecclesiastes 7:20) but when Protestants say this why is the fourth Commandment of honor thy father and mother forgotten? Why then, would Christ not, to the fullest of His capabilities, honor His mother? Remember, Mary's sinless state was achieved solely by the merits of her son, Jesus Christ.
Now let’s look at Genesis 3:15, “I will put enmity between you and the woman, and between your offspring and hers; he will strike at your head, while you strike his heel”. To put this in context this is God talking to the serpent, or Satan. If enmity is put between Satan and the woman that means there is a mutual hatred between Satan and the woman. If Mary, the new Eve, sinned then what would be this hatred between Satan and herself. There would be none!
Let us look now at Mary as the Ark of the Covenant. We have to consider what made the ark holy. The original ark was holy because of what was inside which consisted of the ten commandments, or the Word of God written on stone; the manna, or the miraculous bread which God sent; and the priestly rod of Aaron. Mary similarly held within her the Word of God made flesh, the Bread of Life which conquered death, and the divine eternal priest, Jesus Christ. The golden box which held in it the ten commandments, the manna, and Aaron’s rod represented a pure encasement for God’s Word just as Mary is pure without sin. How else could Christ come into this world then by a sinless mother?
So you see, in these few instances types of Mary in the Old Testament. I wish I had more time to expand upon the reasons why Mary was born without sin. The Immaculate Conception is Biblical and although it may not be explicitly stated in Scripture we still see Mary as being pure and without sin through these types. I would like to leave you with the words of Ambrose,
"Mary, a Virgin not only undefiled but a Virgin whom grace has made inviolate, free of every stain of sin."
Ambrose,Sermon 22:30(A.D. 388),in JUR,II:166