Why don't you point me to that snippet of Scripture. Since you were able to pull the IC dogma out of your hat, you should be able to find the chapter and verse of where Mary did not need a savior, that she alone needed no redeemer, where she alone was without sin.
I'll be waiting... but in the mean time, while the music softly plays in the background, here is something for you to ponder:
1Jo 1:8 If we claim to be without sin, we deceive ourselves and the truth is not in us.
Hbr 4:15 For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are-yet was without sin.
As soon as you point me to that snippet of Scripture that mandates sola Scriptura.
Why would I attempt to prove that, since I have not claimed it?