The Christian thinker Irenaeus (second-third centuries C.E.) states in Against Heresies 3:22:4 that Mary was the second Eve, only Mary did right what Eve did wrong: Eve disobeyed God's command (Genesis 3), whereas Mary called herself "the handmaid of the Lord," saying to the angel, "Be it done for me according to thy word" (in whatever translation Quasten is using).
Irenaeus states that, through her obedience, Mary "became the cause of salvation, both to herself and the whole human race."
I wondered about Irenaeus' statement that Mary caused the salvation of herself. Does that contradict the Catholic doctrine of the Immaculate Conception, which affirms that Mary was conceived without original sin and was therefore sinless?
The Catholic Encyclopedia has a good article about the patristic views on this issue: see here. Some of the fathers believed that Mary sinned. Others called her pure. Some (like Origen) claimed both. The article relies heavily on patristic comparisons of Mary to Eve. It believes that such a parallel supports the Immaculate Conception because Eve wasn't tainted with original sin when she ate the forbidden fruit, since that's the act that brought original sin into the world. So, if Mary is the righteous Eve, it logically follows that she too wasn't tainted with original sin when she yielded to God in obedience. The article also relies on patristic statements that Mary was immaculate and untainted by sin.
But, if Mary were untainted by sin, why would she need Christ to save her? Doesn't Irenaeus affirm that her act of giving birth to Christ led to her own salvation and that of the world? Didn't Mary call God her savior in Luke 1:47?
Both the Catholic Encyclopedia article and the Catholic catechism (Part One: 491-492) state that God did save Mary from sin--when he formed her in a state of sinlessness. And she received this preemptive salvation through the merits of Christ. I'm not sure what this means. Was salvation through Christ's death and resurrection applied to Mary retroactively, before Christ died, the same way many Christians think the Old Testament saints were saved?