Mary was conceived without original sin. This is the dogma of the Immaculate Conception.

But did not Paul say that “all have sinned and are deprived of the glory of God” (Rom 3:23)? Yes, but this is precisely what shows how special Mary is. She is the only human being after the fall who was the one exception.

Mary would bear the Son of God, and God is perfectly holy. It could not be that an imperfect vessel would bear a perfect God. So according to God’s eternal plan, God did not allow Mary to be conceived with any stain of sin.

God wants those that He intends to use to be clean and pure instruments. Such purity was to be from the time of their conception.

Manoah’s wife, who would give birth to Samson, was told “to be careful to take no wine or strong drink and to eat nothing unclean.” (Jgs 13:4). This was because Samson was “to be consecrated to God from the womb” and would “begin the deliverance of Israel from the power of the Philistines” (Jgs 13:5).

Jeremiah, one of the great prophets of Israel, was told by God: “Before I formed you in the womb I knew you, before you were born I dedicated you, a prophet to the nations I appointed you.” (Jer 1:5).

Zechariah was told by the angel Gabriel that his wife Elizabeth would bear a son. John the Baptist became the precursor of Christ. Zechariah was told that John would “be great in the sight of the Lord. He will drink neither wine nor strong drink. He will be filled with the holy Spirit even from his mother’s womb, and he will turn many of the children of Israel to the Lord their God.” (Lk 1:15-16).

Being a deliverer of Israel, a prophet to the nations, a restorer of Israel’s children to the Lord­all these were mighty works of God, for which He raised pure instruments.

But Mary was the greatest instrument of all according to God’s plan. She would be the mother of the Savior, the mother of God Himself. As such, she needed to be a perfectly pure instrument.

But others would still insist that what the Bible says is perfectly true, that “all have sinned” (Rom 3:23a). The only exception is Jesus, “who did not know sin” (2 Cor 5:21). As such, then Mary was subject to original sin as well. Let us follow this trend of thought.

All of us indeed have sinned. We are born with original sin, the sin of our first parents. But through the blood shed for us by Jesus on the cross, our sin has been expiated. We “are justified freely by his grace through the redemption in Christ Jesus, whom God set forth as an expiation, through faith, by his blood, to prove his righteousness because of the forgiveness of sins previously committed” (Rom 3:24-25). We have sinned, but in and through Jesus we are cleansed, if we accept his saving death on the cross by faith.

Now God is not governed by time and space. God transcends time and space. So what God did was to extend to Mary his grace of expiation from sin, won on the cross, but applied backward to the time of Mary’s conception. Thus Mary, like everyone else, was redeemed by the blood of Jesus, but rather than being freed from sin already incurred, she was preserved from original sin.

Can God do that? Of course He can! There is nothing impossible for God! (Lk 1:37).

Indeed notice that with her Magnificat, Mary says her spirit rejoices in God her savior (Lk 1:47). She did not say she will rejoice, but that she already rejoices. But Jesus the Savior was still to be born, and still had to go to the cross to win salvation for all. Thus for Mary, Jesus had already saved her, even before he physically went to the cross. The prophecy of Isaiah rightfully applies to her: “I rejoice heartily in the Lord, in my God is the joy of my soul; for he has clothed me with a robe of salvation, ….. like a bride bedecked with her jewels.” (Is 61:10).

So Mary was conceived without sin.

We also need to see the Immaculate Conception in view of salvation history. When our first parents sinned, there was the first promise of a Redeemer. The Lord God told the devil that there would be enmity between him and the woman and between their offsprings, and that the offspring of the woman would strike him a mortal blow (Gen 3:15). It is a fight between the woman and the serpent. Now the woman is Mary, and so it is a fight between Mary and the devil. If the woman had original sin, then she would be subject to the power of the devil and would not be able to defeat him. So she needed to be free from sin.

And so in the fullness of time, God brought Mary into the world, and then revealed to her His plan. The angel Gabriel addressed her with the words “Hail, favored one!” (Lk 1:28). Another way to put the greeting is “Hail, fully graced.” Mary was full of grace! One who is fully graced cannot have the stain of sin.

And of course, God intended for Mary to bear His own Son. She was to become the mother of God. As the mother of the Holy One, she had to be unstained.

Consider also that there were other humans not covered by Paul’s assertion that all had sinned. These were Adam and Eve. They were born unstained, created in the image  and likeness of God Himself (Gen 1:27). When God looked at what He had created, He “found it very good” (Gen 1:31). God being Who He is, what He creates is perfect. God cannot create something in His image and likeness that is stained in some way.

So Adam and Eve started out with no sin, because there was no sin as yet in the world. Now Mary is the new Eve. If Eve was created sinless, then how much more Mary who would become the mother of God?