Everything that the Catholic Church teaches about Mary is based on what it teaches about Jesus. The Immaculate Conception is the teaching that Mary was conceived without original sin. It is not about Jesus being conceived without sin.
Modern Protestants will point to Romans 3:21-26 Righteousness through Faith
21 But now the righteousness of God has been manifested apart from law, although the law and the prophets bear witness to it, 22 the righteousness of God through faith in Jesus Christ for all who believe. For there is no distinction; 23 since all have sinned and fall short of the glory of God, 24 they are justified by his grace as a gift, through the redemption which is in Christ Jesus, 25 whom God put forward as an expiation by his blood, to be received by faith. This was to show God’s righteousness, because in his divine forbearance he had passed over former sins; 26 it was to prove at the present time that he himself is righteous and that he justifies him who has faith in Jesus.
27 Then what becomes of our boasting? It is excluded. On what principle? On the principle of works? No, but on the principle of faith. 28 For we hold that a man is justified by faith apart from works of law. 29 Or is God the God of Jews only? Is he not the God of Gentiles also? Yes, of Gentiles also, 30 since God is one; and he will justify the circumcised on the ground of their faith and the uncircumcised through their faith. 31 Do we then overthrow the law by this faith? By no means! On the contrary, we uphold the law.
To understand this, you need to know that Paul was writing to a Jewish and Gentile Christian Church in Rome. The Jewish Christians were always trying to hold themselves above the Gentile Christians and push the Jewish works of the law on them. Paul is telling this Christians community, that both groups have sinned, not just the Gentiles. This is the “all” that Paul is referring to. All of those Christians. Both Protestants and Catholics agree that those without reason, like babies and people who are mentally Impaired can’t commit personal sin.
Protestants also point to Luke 1:46-49 Mary’s Song of Praise 46“My soul magnifies the Lord,47 and my spirit rejoices in God my Savior, 48 for he has regarded the low estate of his handmaiden. For behold, henceforth all generations will call me blessed; 49 for he who is mighty has done great things for me,
and holy is his name. Protestants claim that since Mary rejoices in her Savior, that she needed saving. Therefore, she was not sinless.
Catholics agree that Mary needed Jesus as her Savior. Since God is outside of time and space, Jesus used the Grace that He merited, through His sacrifice on the cross, to save Mary before He came into this world Through Mary. The analogy often used is that if you save a person from falling into a mud puddle you saved them from getting muddy Before they got muddy. You can think of it as Mary being Preemptively Saved by Jesus before He entered this world to save the rest of us. Jesus saved Mary so that she could be the Holy Vessel or New Ark of the Covenant for the Word made Flesh to be contained in. John 1:1 tells us in the beginning was the Word, and the Word was with God and the Word was God. The original Ark of the Covenant was made with acacia wood which didn’t rot. The wood was overlaid with gold so it would always shine. The Ark was covered with a blue cloth as it was being carried around as shown in Numbers ch4 4 This is the service of the sons of Kohath in the tent of meeting: the most holy things. 5 When the camp is to set out, Aaron and his sons shall go in and take down the veil of the screen, and cover the ark of the testimony with it; 6 then they shall put on it a covering of goatskin, and spread over that a cloth all of blue, and shall put in its poles. The Ark had God’s Word in the 10 Commandments and Aaron’s staff that budded to show his authority and some of the miraculous mana from the desert. The Ark was so Holy that no one could touch it. Uzzah was struck dead for touching the Ark in 2 Samuel 6:7 In the Book of Revelation at the end of chapter 11, John is looking into Heaven and he writes, “God’s temple in heaven was opened, and within His Temple was seen the Ark of His covenant...a woman clothed with the sun".
Compare these parallels between 2 Sam 6:5-11 about David with the Ark and Luke 1:43,44 & 56 about Elizabeth with Mary.
1. David dances for joy in 2 Sam 6:5 and John leaps for joy in Elizabeth’s womb in Luke 1:44. 2. David calls out, “How can the ark of the Lord come to me?” in 2 Sam 6:9 and Elizabeth calls out, “why is this granted me, that the mother of my Lord should come to me?” in Luke 1:43. 3. The Ark of the Lord remained in the house of Obed-edom the Gittite a few miles outside Jerusalem for three months, and the Lord blessed Obed-edom and his whole house in 2 Sam 6:11. Mary remained about three months with Elizabeth in Luke 1:56 a few miles outside Jerusalem.
The roots of Mary being sinless go all the way back to the Book of Genesis, through Luke to the Book of Revelation. In Genesis 3.15, we see a foreshadowing of Mary as the New Eve who was born without sin like the original Eve. "I will put enmity between you and the woman, and between your seed and her seed: he shall bruise your head, and you shall bruise his heel." God tells the serpent that He will put enmity between the woman’s seed and the Satan’s seed. At this time in history, it was understood that the “seed” was in the man’s semen which grew inside the fertile “soil” of a woman’s womb. The mention of a Woman’s Seed was quite extraordinary.
In the New Testament Jesus calls Mary Woman in John ch2 at the Wedding at Cana. Jesus also calls Mary woman when He gives her to John in ch19. Jesus calls Mary “Woman” to connect her back to the Eve who is called Woman n Genesis 2:22. The title is both respectful and theologically important in revealing Mary’s role in salvation history.
In Revelation ch12, we find a Woman in Heaven who gives birth to the Man child that rules with a rod of iron. The Man child that rules with a rod of iron is Jesus. Only One Woman gave birth to Jesus. That Woman is Mary. Eve is an earlier type of the Woman Mary, and the nation of Israel also gave birth to Mary through its continued existence, but these are both secondary concepts.
In Luke ch1 we find The Birth of Jesus Foretold 26 In the sixth month the angel Gabriel was sent from God to a city of Galilee named Nazareth, 27 to a virgin betrothed to a man whose name was Joseph, of the house of David; and the virgin’s name was Mary. 28 And he came to her and said, “Hail, full of grace,[e] the Lord is with you!” 29 But she was greatly troubled at the saying, and considered in her mind what sort of greeting this might be. 30 And the angel said to her, “Do not be afraid, Mary, for you have found favor with God. 31 And behold, you will conceive in your womb and bear a son, and you shall call his name Jesus. 32 He will be great, and will be called the Son of the Most High; and the Lord God will give to him the throne of his father David, 33 and he will reign over the house of Jacob forever; and of his kingdom there will be no end.” 34 And Mary said to the angel, “How can this be, since I have no husband?” 35 And the angel said to her, “The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the child to be bornwill be called holy, the Son of God. 36 And behold, your kinswoman Elizabeth in her old age has also conceived a son; and this is the sixth month with her who was called barren. 37 For with God nothing will be impossible.” 38 And Mary said, “Behold, I am the handmaid of the Lord; let it be to me according to your word.” And the angel departed from her.
The Greek word in the Gospel is kecharitomene. It is a perfect passive participle of the verb charitoo. A perfect passive participle is very strong. In addition, charitoo belongs to a group of verbs ending in omicron omega. They have in common that they mean to put a person or thing into the state indicated by the root. Therfeore, leukos means white, so leukoo means to make white. Then charitoo should mean to put into charis. That word charis can mean either favor or grace. But if we translate by favor, we must keep firmly in mind that favor must not mean merely that God, as it were, sits there and smiles at someone, without giving anything. That would be Pelagian: salvation possible without grace. So, for certain, God does give something, and that something is grace, are share in His own life. So charitoo means to put into grace. But then too, kecharitomene is used in place of the name "Mary". This is like our English usage in which we say, for example, someone is Mr. Tennis. That means he is the ultimate in tennis. So then kecharitomene should mean "Miss Grace", the ultimate in grace. Therefore, we could reason that fullness of grace implies an Immaculate Conception.
The Immaculate Conception refers to the dogma that the Blessed Virgin Mary was conceived without any stain of Original Sin in preparation for becoming the Mother of God, the Son Jesus Christ.
Before the creation of the world, God the Father chose the Blessed Virgin Mary to be the Mother of his Son, Jesus Christ. The Archangel Gabriel announced to her that she was "full of grace" (Luke 1:29)—or God's "favored one," as in some Scripture translations—indicating her unique worthiness to conceive the Son of God; she "was enriched by God with the gifts which befit such a role" (LG 56). From the very beginning the Church has believed not only that the Blessed Virgin Mary was a virgin but also that she was not conceived with any stain of Original Sin into which everyone is conceived after the sin of Adam and Eve. This unique privilege enabled her to fulfill perfectly her unique mission as the Mother of God. God the Father blessed the Mother of his Son more than any other created person "in Christ with every spiritual blessing in the heavenly places [and chose her] in Christ before the foundation of the world, to be holy and blameless before him in love" (Bl. Pius IX, Ineffabilis Deus : DS 2803). (Cf. CCC 966) The Church has celebrated the Immaculate Conception of the Blessed Virgin Mary with a feast since perhaps as early as the fifth century, and it was made a Holy Day of Obligation in 1708.
December 8th marks the feast of the Immaculate Conception. It celebrates an important point of Catholic teaching, and it is a holy day of obligation.
The history of this doctrine:
Initially, the Christian church taught a belief that is close to modern conservative Protestantism: simply that Mary was a virgin at the time of the conception of Jesus.
Eadmer (1066-1124), a monk at Christ Church, Canterbury. England was one of the first proponents of the doctrine of the Immaculate Conception. He discussed it in his book "De Conceptione sanctae Mariae."
St. Thomas Aquinas (1225-1274) and St. Bonaventure (1221-1274) "... believed that Mary was completely free from sin, but that she was not given this grace at the instant of her conception." Their beliefs were supported by the Dominicans.
In 1476, Pope Sixtus IV established the feast of the Immaculate Conception to be observed annually on DEC-08 -- nine months before the Church celebrates the anniversary of Mary's birth. But the Roman Catholic laity and clergy was permitted to accept or reject the concept. This freedom was confirmed at the Council of Trent in the mid-16th century. However, Oxford Franciscans William of Ware and Blessed John Duns Scotus supported the full doctrine.
By having Mary free of original sin resulted in both Mary's and Jesus' conceptions being miraculous. The concept of the immaculate conception -- that Mary was conceived without sin while a pre-embryo around 20 BC --- gained support in the church.
It was only in modern times that scientists determined that both the woman and man contributed genetic information to the production of offspring. In ancient times, the man was regarded as being totally responsible for the start of pregnancy. The only role of the woman was to nurture the growing embryo, and later the fetus. A good analogy is the act of planting a seed in earth. The woman's role was similar to that of the earth. The soil has no role other than furnishing nutrients to the seed and later to the plant.
When the woman's role in conception was discovered by medical scientists, the Roman Catholic Church faced a problem. For the first time, Mary was seen to play a direct role in Jesus' conception. Her contribution would have been expected to pass original sin onto Jesus -- an intolerable arrangement because the Church has taught that Jesus was without sin at his birth and during his life on earth.
The Church had two choices: ~ To declare that Mary did not pass original sin onto Jesus at the time of his conception, or ~ To declare that Mary herself was free of sin when she was conceived. They selected the latter route.
It is now a required belief for Roman Catholics. In 1854, Pope Pius IX proclaimed in his Bull Ineffabilis that:
"...We declare, pronounce and define that the doctrine which asserts that the Blessed Virgin Mary, from the first moment of her conception, by a singular grace and privilege of almighty God, and in view of the merits of Jesus Christ, Savior of the human race, was preserved free from every stain of original sin is a doctrine revealed by God and, for this reason, must be firmly and constantly believed by all the faithful." 2
Here are 8 things you need to know about the teaching and the way we celebrate it.
1. Who does the Immaculate Conception refer to?
There's a popular idea that it refers to Jesus' conception by the Virgin Mary. It doesn't. Instead, it refers to the special way in which the Virgin Mary herself was conceived. This conception was not virginal. (That is, she had a human father as well as a human mother.) But it was special and unique in another way. . .
2. What is the Immaculate Conception?
The Catechism of the Catholic Church explains it this way: 490 To become the mother of the Savior, Mary “was enriched by God with gifts appropriate to such a role.” The angel Gabriel at the moment of the annunciation salutes her as “full of grace”. In fact, in order for Mary to be able to give the free assent of her faith to the announcement of her vocation, it was necessary that she be wholly borne by God's grace. 491 Through the centuries the Church has become ever more aware that Mary, “full of grace” through God, was redeemed from the moment of her conception.
That is what the dogma of the Immaculate Conception confesses, as Pope Pius IX proclaimed in 1854: The most Blessed Virgin Mary was, from the first moment of her conception, by a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Savior of the human race, preserved immune from all stain of original sin.
3. Does this mean Mary never sinned?
Yes. Because of the way redemption was applied to Mary at the moment of her conception, she not only was protected from contracting original sin but also personal sin. The Catechism explains: 493 The Fathers of the Eastern tradition call the Mother of God “the All-Holy” (Panagia), and celebrate her as “free from any stain of sin, as though fashioned by the Holy Spirit and formed as a new creature”. By the grace of God Mary remained free of every personal sin her whole life long. “Let it be done to me according to your word. . .”
4. Does this mean Mary didn't need Jesus to die on the Cross for her? No. What we've already quoted states that Mary was immaculately conceived as part of her being “full of grace” and thus "redeemed from the moment of her conception" by "a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Savior of the human race." The Catechism goes on to state: 492 The “splendor of an entirely unique holiness” by which Mary is “enriched from the first instant of her conception” comes wholly from Christ: she is “redeemed, in a more exalted fashion, by reason of the merits of her Son”. The Father blessed Mary more than any other created person “in Christ with every spiritual blessing in the heavenly places” and chose her “in Christ before the foundation of the world, to be Holy and blameless before Him in love”. 508 From among the descendants of Eve, God chose the Virgin Mary to be the mother of His Son. “Full of grace,” Mary is “the most excellent fruit of redemption” (SC 103): from the first instant of her conception, she was totally preserved from the stain of original sin and she remained pure from all personal sin throughout her life.
5. How does this make Mary a parallel of Eve? Adam and Eve were both created immaculate, without original sin or its stain. They fell from grace, and through them mankind was bound to sin. Christ and Mary were also conceived immaculate. They remained faithful, and through them mankind was redeemed from sin. Christ is thus the New Adam, and Mary the New Eve. The Catechism notes: 494 . . . As St. Irenaeus says, “Being obedient she became the cause of salvation for herself and for the whole human race.” Hence not a few of the early Fathers gladly assert. . .: “The knot of Eve's disobedience was untied by Mary's obedience: what the virgin Eve bound through her disbelief; Mary loosened by her faith.” Comparing her with Eve, they call Mary “the Mother of the living” and frequently claim: “Death through Eve, life through Mary.”
6. How does this make Mary an icon of our own destiny? Those who die in God's friendship and thus go to heaven will be freed from all sin and stain of sin. We will thus all be rendered "immaculate" (Latin, immaculatus = "stainless") if we remain faithful to God. Even in this life, God purifies us and trains us in holiness and, if we die in his friendship but imperfectly purified, he will purify us in purgatory and render us immaculate. By giving Mary this grace from the first moment of her conception, God showed us an image of our own destiny. He shows us that this is possible for humans by his grace. John Paul II noted: In contemplating this mystery in a Marian perspective, we can say that "Mary, at the side of her Son, is the most perfect image of freedom and of the liberation of humanity and of the universe. It is to her as Mother and Model that the Church must look in order to understand in its completeness the meaning of her own mission" (Congregation for the Doctrine of the Faith, Libertatis conscientia, 22 March, 1986, n. 97; cf. Redemptoris Mater, n. 37). Let us fix our gaze, then, on Mary, the icon of the pilgrim Church in the wilderness of history but on her way to the glorious destination of the heavenly Jerusalem, where she [the Church] will shine as the Bride of the Lamb, Christ the Lord [General Audience, March 14, 2001].
7. Was it necessary for God to make Mary immaculate at her conception so that she could be Jesus' mother? No. The Church only speaks of the Immaculate Conception as something that was "fitting," something that made Mary a "fit habitation" (i.e., suitable dwelling) for the Son of God, not something that was necessary. Thus in preparing to define the dogma, Pope Pius IX stated: And hence they [the Church Fathers] affirmed that the Blessed Virgin was, through grace, entirely free from every stain of sin, and from all corruption of body, soul and mind; that she was always united with God and joined to him by an eternal covenant; that she was never in darkness but always in light; and that, therefore, she was entirely a fit habitation for Christ, not because of the state of her body, but because of her original grace. For it was certainly not fitting that this vessel of election should be wounded by the common injuries, since she, differing so much from the others, had only nature in common with them, not sin. In fact, it was quite fitting that, as the Only-Begotten has a Father in heaven, whom the Seraphim extol as thrice holy, so he should have a Mother on earth who would never be without the splendor of holiness [Ineffabilis Deus].
8. How do we celebrate the Immaculate Conception today? In the Latin rite of the Catholic Church, December 8th is the solemnity of the Immaculate Conception. In the United States and in a number of other countries, it is a holy day of obligation. The constant faith (tradition: paradosis) of the Church attests to the belief in the special preparation of the holiness of the person of Mary to bear in her body the most holy person of the Son of God. Church Fathers:
implicitly found in the Fathers of the Church in the parallelism between Eve and Mary (Irenaeus, Lyons, 140? - 202?);
Found in the more general terms about Mary: 'holy', 'innocent', 'most pure', 'intact', 'immaculate' (Irenaeus, Lyons, 140?-202?; Ephraem, Syria, 306-373; Ambrose, Milan, 373-397);
Explicit language: Mary - free from original sin (Augustine, Hippo, 395-430 to Anselm, Normandy, 1033-1109);
celebrated a Feast of the Conception of Mary in the 8th to the 9th Century;
celebrated a Feast of the Conception of Mary in the 12th Century;
A record of the feast in the 11th Century in Great Britain; in the 12th Century in Normandy;
Record in many churches of a Feast of the Conception of Mary in France, Germany, Italy, and Spain in the 12th Century (Bernard, Clairvaux, 1090-1153);
was noted for the opposition to the Immaculate Conception from some of the great doctors of scholasticism. The celebration of the feast was not denied though. The difficulty arose from the meaning of the universal redemption through Christ.
Franciscan theologians solved the difficulty--Christ, the most perfect mediator, preserved Mary from original sin by an equally perfect act of healing. Duns Scotus (Scotland, 1266-1308) explained that the Immaculate Conception came through God's application of the grace of Christ beforehand.
From 15th Century:
the Feast was universally celebrated; and Christian piety introduced an oath to defend the belief in the Immaculate Conception to be taken not only by Religious, but also by non-Religious and at the Universities (e.g., Paris, 1497; Cologne, 1499; Vienna, 1501, etc.)
1854, Pope Pius IX, infallibly defined, ex cathedra:
'The Blessed Virgin Mary, in the first instant of her conception, by a singular grace and privilege of Almighty God, and in view of the foreseen merits of Jesus Christ, the savior of the human race, was preserved free from all stain of original sin.'