The French Dominican and leading theologian of the 20th century Garrigou-Lagrange teaches in His Three Ages of the Interior Life that it is "a certain doctrine" that Our Lady is the dispenser of all graces and mediatrix for all mankind..
Thus even this 'neo-Thomist' theologian acknowledges without hesitation what Pope Leo XIV is placing in question today: that Our Lady is he Mediatrix and Co-Redemptrix of mankind. He further reminds us that every particular grace is distributed to us by Mary.
Fr. Reginald Garrigou-Lagrange
That Mary obtains for us and distributes to us all graces is a certain doctrine, according to what we have just said about the mother of all men. As mother, she is interested in their salvation, prays for them, and obtains for them the graces they receive.
In the Ave Maris Stella we read: Salve vincla reis, Profer lumen caecis, Bona cuncta posce, Mala nostra pelle. Break the sinner’s fetters, To the blind give day, Ward all evils from us, For all blessings pray. In an encyclical on the Rosary, Leo XIII says: According to the will of God, nothing is granted to us except through Mary; and, as no one can go to the Father except through the Son, so then no one can draw near to Christ except through Mary.”[24]
The Church, in fact, turns to Mary to obtain graces of all kinds, both temporal and spiritual; among these last, from the grace of conversion up to that of final perseverance, to say nothing of those needed by virgins to preserve virginity, by apostles to exercise their apostolate, by Martyrs to remain firm in the faith.
In the Litany of Loreto, which has been universally recited in the Church for many centuries, Mary is for this reason called: “Health of the sick, refuge of sinners, comforter of the afflicted, help of Christians, Queen of Apostles, of Martyrs, of Confessors, of Virgins.”
Thus all kinds of graces are distributed by her, even, in a sense, those of the Sacraments; for she merited them for us in union with Christ on Calvary. In addition, she disposes us, by her prayer, to approach the Sacraments and to receive them well. At times she even sends us a priest, without whom this sacramental help would not be given to us.
Finally, not only every kind of grace is distributed to us by Mary, but every grace in particular. Is this not what the faith of the Church says in the words of the Hail Mary: “Holy Mary, Mother of God, pray for us sinners now and at the hour of our death. Amen”?
This “now” is said every moment in the Church by thousands of Christians who thus ask for the grace of the present moment. This grace is the most individual of graces; it varies with each of us, and for each one of us at every moment. If we are distracted while saying this word, Mary, who is not distracted, knows our spiritual needs of every instant, and prays for us, and obtains for us all the graces that we receive. This teaching, contained in the faith of the Church and expressed by the common prayers (lex orandi lex, credendi), is based on Scripture and Tradition.
Even during her earthly life, Mary truly appears in Scripture as the distributor of graces. Through Mary, Jesus sanctified the Precursor when she went to visit her cousin Elizabeth and sang the Magnificat. Through His mother, Jesus confirmed the faith of the disciples at Cana, by granting the miracle that she asked. Through her, He strengthened the faith of John on Calvary, saying to him: “Behold thy mother.” Lastly, by her the Holy Ghost came down upon the Apostles, for she was praying with them in the Cenacle on Pentecost day when the Holy Ghost descended in the form of tongues of fire.[25]
With even greater reason after the Assumption and her entrance into glory, Mary is the distributor of all graces. As a Beatified Mother knows in Heaven the spiritual needs of her children whom she left on earth, Mary knows the spiritual needs of all men. Since she is an excellent mother, she prays for them and, since she is all powerful over the heart of her Son, she obtains for them all the graces that they receive, all which those receive who do not persist in evil. She is, it has been said, like an aqueduct of graces and, in the mystical body, like the virginal neck uniting the head to its members.
When we treat of what the prayer of proficients ought to be, we shall speak of true devotion to Mary as it was understood by Blessed Grignion de Montfort. Even now we can see how expedient it is frequently to use the prayer of mediators, that is, to begin our prayer by a trusting, filial conversation with Mary, that she may lead us to the intimacy of her Son, and that the holy soul of the Savior may then lift us to union with God, since Christ is the way, the truth, and the life.
The Three Ages of the Interior Life, Vol. 1,
Imprimatur & Nihil Obstat, Baronius Press Ltd, 1948, Chap. 6