I’m sorry, I’m still a little confused. What does it mean by “fitting?” I’ve read the wiki on Immaculate Conception, and I’m not fully understanding it.
So the doctrine is saying it wasn’t necessary that Mary be sinless to carry Jesus, and this preservation from original sin was not for Jesus?
Welcome to CAF.
By applying the merits of Christ to His mother “outside of time” (and so Baptizing her into Christ in advance), Jesus was able both to come from the line of Adam (through Mary) and take on an undamaged humanity like that of Adam (and Eve) before the Fall. Indeed, this was clearly God’s plan from the start, per Genesis 3:15, which places “the woman” (a New Eve) in opposition to the serpent, bringing the Messiah out of that, the Seed of the woman pitted against the seed of the serpent. Otherwise, Jesus would not have taken on a sinless and uncorrupted human nature, but our fallen nature, and so He could not have been the New Adam, but a fallen son of Adam like all the rest of us.
One must also keep in mind that the sin which plunged humanity into darkness was that of Adam, not of Eve. Eve did sin first; but until Adam, as head of the human family, joined her in sin (instead of remaining faithful and interceding for her), humanity as a whole was not cut off from God, and this is the problem which the New Adam came to repair; and, since woman was not the cause of mankind’s final break with God, God takes the creation of woman and re-builds the human race from her (a New Eve - Mary), using her to bring the New Adam (the God-man) into the world which, in the very same dynamic, makes this New Eve’s sinlessness possible.
Regarding fittingness, both in scripture and theology, the argument from fittingness supports many doctrines. For example, Hebrew 2.10: “For it was fitting that he, for whom and by whom all things exist, in bringing many sons to glory, should make the founder of their salvation perfect through suffering.” And Hebrews 7:26: “For it was indeed fitting that we should have such a high priest, holy, innocent, unstained, separated from sinners, and exalted above the heavens.”
God is free to do anything in whatever manner He chooses, but the way He does things is always perfect and most fitting for what is to be accomplished. Thus, e.g., with the Immaculate Conception of the Blessed Virgin Mary it was most fitting that His Son be conceived and born to a woman preserved from Original Sin, and thus it was fitting that the Mother of God be a virgin inviolate throughout her life. This fittingness was recognized quickly by the Fathers who so readily see her as the New Eve and the Ark of the New Covenant.