Just for Catholics - http://www.justforcatholics.org/immaculate.htm
THE DOGMA OF THE IMMACULATE CONCEPTION
The modern Catholic Church teaches dogmatically that Mary was conceived without sin. The Catechism (paragraph 491) states:
Through the centuries the Church has become ever more aware that Mary, 'full of grace' through God (Luke 1:28) 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.
History
How was the idea of Mary's immaculate conception introduced in the catholic church? The doctrine was not a tradition in the early centuries of the church. Some Church Fathers taught that Mary led a sinless life, but they did not teach that she was conceived without original sin. On the contrary the Fathers opposed the heresy of Pelagius who insisted that Adam's sin was not imputed to the human race. For instance, Augustine writes: "He [Christ], therefore, alone having become man, but still continuing to be God, never had any sin, nor did he assume a flesh of sin, though born of a maternal flesh of sin" (De Peccatorum Meritis, Bk II, Ch 38). Christ alone never had any sin.
A feast of Mary's conception was celebrated in the Eastern church as early as the seventh century (and later in the West), but that does not imply a belief in "immaculate" conception. In fact, to this day the Orthodox Church does not accept the doctrine.
In the 13th-century, John Duns Scotus promoted the doctrine of the Immaculate Conception. The Franciscan monks continued to preach and defend the doctrine, but it was opposed in the 12th-century by St. Bernard of Clairvaux, by St. Thomas Aquinas in the 13th-century and subsequently by the Dominican friars.
In the 15th-century the Franciscan Pope Sixtus IV established a feast of the Immaculate Conception to be celebrated on December 8.
Finally in 1854 Pope Pius IX issued a solemn decree, Ineffabilis Deus, declaring the Immaculate Conception an essential dogma for all the church.
Scripture
Catholic scholars acknowledge that this doctrine is not explicitly revealed in Scripture. The Catholic Encyclopaedia admits, "No direct or categorical and stringent proof of the dogma can be brought forward from Scripture."
The Catechism refers to Luke 1:28 for scriptural support. But "full of grace" could not possibly mean conceived without sin, for the very same word is used in Ephesians 1:6 referring to ALL believers. Certainly no-one would argue that all Christians are conceived without sin!
Contrary to the Roman Catholic teaching, the Scripture plainly teaches that all Adam's descendents share his sinful nature: "Therefore, just as through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned" (Romans 5:12). Therefore all Adam's children need to be saved. Mary herself, a natural descendant of Adam, calls God "my savior" (Luke 1:47). Evidently she did not know the Roman Catholic doctrine of the Immaculate Conception!
Of Christ alone, the eternal Son who was supernaturally conceived by the Holy Spirit in the womb of the virgin woman, it is ever expressly stated that He was "without sin" (Hebrews 4:15). Christ alone is immaculate from conception; therefore He alone is qualified to die in the place of sinners. Christ, who knew no sin, "bore our sins in His own body on the tree" (1 Peter 2:24).
In Ineffabilis Deus, Pope Pius IX also appealed to Genesis 3:15 as "unmistakable evidence that she has crushed the poisonous head of the serpent." He also states that with and through Christ, Mary was "eternally at enmity with the evil serpent, and most completely triumphed over him, and thus crushed his head with her immaculate foot."
But the Bible does not say that Mary crushed the serpent's head. Speaking to the serpent, the Lord says:
And 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.
The woman's Seed, the Messiah, not the woman, bruised the serpent's head.
The paintings of the Immaculate crushing the serpent's head were inspired from a incorrect translation of Genesis 3:15 based on the Latin Vulgate: "I will put enmities between thee and the woman, and thy seed and her seed: she shall crush thy head, and thou shalt lie in wait for her heel" (Douay-Rheims Bible). Modern Catholic Bibles, such as the New American Bible, correct the mistake: "I will put enmity between you and the woman, and between your offspring and hers; He will strike at your head, while you strike at his heel."
Yet Mary is still portrayed crushing Satan's head. Let us not be misled by false images and false doctrine. Nobody but Jesus fulfilled the great prophecy and overcame our deceptive enemy. "For this purpose the Son of God was manifested, that he might destroy the works of the devil" (1 John 3:8). Through His death, Jesus destroyed "him who had the power of death, that is, the devil, and release[ed] those who through fear of death were all their lifetime subject to bondage" (Hebrews 2:14,15). Let us therefore trust in Him alone to give us victory over Satan, sin and death.
Shipwreck in the Faith
The implications of the Catholic dogma are very serious. Pope Pius IX solemnly warned: "Hence, if anyone shall dare -- which God forbid! -- to think otherwise than as has been defined by us, let him know and understand that he is condemned by his own judgment; that he has suffered shipwreck in the faith; that he has separated from the unity of the Church; and that, furthermore, by his own action he incurs the penalties established by law if he should express in words or writing or by any other outward means the errors he thinks in his heart" (Ineffabilis Deus).
The Roman Catholic magisterium would have us believe a novel doctrine (that is neither taught in the Scriptures nor in the writings of the Church Fathers) as an essential article of the Christian faith. But we are convinced that the Scriptures are able to make us wise unto salvation through faith in Christ Jesus (2 Timothy 3:15). We don't need any extra-biblical doctrines for our salvation. In fact, it is the Roman Church that has suffered "shipwreck in the faith" by embracing a doctrine that is contrary to the Bible; and "separated from the unity of the Church" which for centuries knew nothing of the theological inventions of Rome.
