The Roman Catholic Church believes the dogma is supported by scripture and by the writings of many of the [[Church Fathers]], either directly or indirectly. Roman Catholic theology maintains that since Jesus became [[incarnation|incarnate]] of the Virgin Mary, she needed to be completely free of sin to bear the Son of God, and that Mary is "redeemed 'by the grace of [[Jesus Christ|Christ]]' but in a more perfect manner than other human beings" (Ott, ''Fund.'', Bk 3, Pt. 3, Ch. 2, §3.1.e).
The doctrine is generally not shared by either Eastern Orthodoxy or by [[Protestantism]]. Protestantism rejects the doctrine because it is not explicitly spelled out in the [[Bible]]. Protestants and Eastern Orthodox often say that the immaculate conception of the [[Theotokos]] would contradict the doctrine of the [[salvation|redemption]] of humanity, as the Virgin Mary would have been cleansed before Christ's own incarnation, making his function superfluous. Orthodox Christians say that St. [[Augustine of Hippo|Augustine]] (d. 430), whose works were not well known in Eastern Christianity until perhaps the 17th and 18th centuries, has influenced the theology of sin that has generally taken root in the West. Many Orthodox consider unnecessary the doctrine that Mary would require purification prior to the Incarnation. Eastern Orthodox
theologians believe that the references among the Greek and Syrian Fathers to Mary's purity and sinlessness may refer not to an ''a priori'' state but to her conduct after birth.
Roman Catholics counter with Scripture (e.g., [[Romans]] 5, [[Wisdom of Solomon]] 2:24, [[I Corinthians]] 15:21, the experience of St. [[John the Forerunner|John the Baptizer]] in his mother's womb, etc.) and the writings of Church Fathers prior to St. [[Augustine of Hippo|Augustine]].