I answered an objection to my recent article on this topic at National Catholic Register:
Of course, Jesus is our Savior, and the source of all the grace (as I made quite clear in my paper), which He then chooses to pass through Mary to us. No contradiction whatsoever. It only is for those accustomed to thinking in unbiblical either/or terms. A hose is not the ultimate source of water. An electric wire is not the source of electricity or a phone signal. The computer you’re looking at right now is not the source of these words of mine (I am). Jesus is the source. People like Paul passed along his grace, as channels. Likewise, Mary, in Catholic thought.
And some more thoughts presently and in my combox:
Critics of the doctrine think that if (or just because) all grace comes through her, she is the source, but that doesn’t follow. If all the drinking water in the world somehow had to go through one single pipe, it still wouldn’t follow that the pipe was the ultimate source of the water. The nature of the pipe is that it doesn’t produce water; it only carries it. That’s how the Blessed Virgin Mary is as regards divine grace.
It’s the distinction, again, between Mary being the source of all grace or the optional choice, by God, to be the vessel of all grace that originates with him. Critics don’t like it because they regard it as 1) unbiblical (it’s harmonious with scriptural notions, as I have shown) and 2) taking away from the prerogatives of God (which it doesn’t do at all).
Mary always directs us towards Jesus. She is a totally unique “pipe.” It’s like the Church being a vessel of salvation, whether people are aware of it or not. Mary is the vessel of the grace from God, whether people are aware of it or not.
(originally 8-15-17 on Facebook)
Photo credit: The Madonna in the Church (c. 1440), by Jan van Eyck (c. 1390-1441) [public domain / Wikimedia Commons]