Paul S said:
I'll certainly agree that it's doctrine that Mary is a mediatrix. We are all mediators and mediatrices, since we all co-operate in bringing God's grace to the world. But do all graces flow through Mary?
Octobri Mense says that, but is that the official teaching or is it Pope Leo's opinion? I do know it hasn't been defined like the Immaculate Conception and the Assumption.
I don't have any problems with the doctrine - I've just always heard that it's still optional. But if this has always been the teaching of the Church, then, like Humanae Vitae or Ordinatio Sacerdotalis, we must assent to it.
Of course, doctrines are not optional, even if they have not yet been well defined or made dogmatic. I believe religious assent is the minimal level required, but don't hold me to that
Her role as Mediatrix of all graces was implicit in the Church Fathers, and explicity stated by the 12th century that I am aware of. St. Bernard of Clarivaux (d 1153) said "God has willed that we should have nothing that did not pass through the hands of Mary." Saint Bernardine of Siena (d 1444), Fransiscan, said "I do not hestitate to say that she has received a certain jurisdiction over all graces . . They are administered through her hands to whom she pleases, when she pleases, as she pleases, and as much as she pleases." (quotes from Dictionary of Mary, Mediatrix,, pg 322)
Lumen Gentium of course is a towering document reflecting the doctrines of the Church.
Here is something I discovered in scripture recently . . it started with something I read by the Last Eastern Father, St John the Damascene. I would have to find the poem/hymn he wrote about her conception to give you the full sense of what was being said, but in it he referred to Mary as a tree by living waters, the tree of life.
Things started to come together in my understanding . . Jesus is the fruit of Mary, of her womb . .. Mary the Tree of Life has given us her fruit the God-Man; God, through Mary has done this, . this even ties into the Eucharist. But here, I began to see the connection between Mary and the Tree of Life.
The Early Church referred to Mary as the Tree of Life . . .this is very interesting and significant I believe.
The following list of titles of Mary drawn exclusively from the
patristic writing compiled by Sister Marie Stephen O.P. of Rosary
College from "The Blessed Virgin in the Fathers of the First Six
Centuries", by Fr. Thomas Linius, C.SS.R., published by Burns and
Oates in 1893.
Most holy paradise of Eden.
Tree of good foliage.
Tree of
Life. Earth unsown.
Cloud raining upon the earth. Burning bush
unconsumed. Open Meadow. Blossoming rod of Aaron.
Fruitful olive
tree. Tree of the Father. Flower of the field. Lily of the
valley. Spotless lily that brought forth Christ the unfading rose.
Garden enclosed. Garden fertile though untilled. Vine fruitful with
grapes. Vine bringing forth a pleasant odor. Rod that blossomed
forth Christ as the flower. Mead of sweet savor. Unleavened meal
banishing from food the bitterness of death. Root of the loveliest
Flower that blooms. Flower unfading. Garden of the Father.
Root of
all good things. Vine bearing beautiful grapes.
http://www.mgardens.org/BibLit-Symb-QM.html
These are some of the implicit references to Mary's role as Mediatrix of all graces . . I bolded several above which are very interesting in this regard.
Cloud raining upon the earth is the very picture of Mary being the Mediatrix of all graces, including being the Dispensrix of all graces as well.
Root of all good things being another. But right now I am focusing on the title Tree of Life.
The Tree of Life disappears at the beginning of the world, with the fall of Adam, and does not make an appearance,
by name, until Revelation.
Now, jump to Revelation. At the end of this book, John describes a scene where he sees the throne of God and of the Lamb, and from their throne flows a River . . and in the midst of the river and on either side is the Tree of Life .
Rev 22:1 And he shewed me a pure river of water of life, clear as crystal, proceeding out of the throne of God and of the Lamb.
Rev 22:2 In the midst of the street of it, and on either side of the river, was there the tree of life, which bare twelve manner of fruits, and yielded her fruit every month: and the leaves of the tree were for the healing of the nations.
Follow with me here for a little . . . Many of the Fathers have seen in this passage a reference to the Trinity God the Father, God the Son, and God the Holy Spirit . .the latter being symbolically represented by the River of Living Water proceeding from the Father and the Son (our filioque in scripture

). Look what is in the midst and on either side of the River . .. The Tree of Life . . .
It is not at all a stretch of the imagnation to see The Tree of Life here symbolically representing Mary, being planted in and on either side of this Rive of Life. . . And look at what flows through Mary? The River of Life, the River of Water of Life symbolically representing the Holy Spirit. And this tree bears fruit and the leaves are for the healing of nations. I can easily see Mary, Mediatrix of all graces bieng portrayed here in scripture.
These treasures in scripture are so wonderful . .. What I find about Mary in scripture is that where she is found, the scriptures uses very few words, but the words used are so full of meaning . . I don't know if we can plumb their depths.
John Paul pray for us!