1 Tim 2:5 NIV
5 For there is one God and one mediator between God and men, the man Christ Jesus,
From Wikipedia, the free encyclopedia
"Mary, Mediatrix of all graces" is a title that some give to Mary the mother of Jesus, in line with a belief that all the graces that her son gives come through
her.
Proposal for formal definition by the Catholic Church
In 1896, French Jesuit priest René-Marie de la Brosse published a proposal that the Pope should make a dogmatic definition about the role of Mary in the distribution of all graces, but did not require that it be in the form of declaring her to be the mediatrix of all graces.
Eight years later, Belgian Redemptorist priest François Xavier Godts wrote a book proposing precisely that it be defined that Mary is the mediatrix of all graces.
http://www.ewtn.com/library/MARY/MEDIATRI.htm
Secondly, Mary is invoked in the Church under the title Mediatrix of all grace. All the graces which flow from the redemption of Jesus Christ are granted to the human family through the motherly intercession of Mary. Mary mediated Jesus Christ, the Author of all graces, to the world when she agreed to be the human mother of God made man (cf. Lk 1:38). And from the cross at Calvary (Jn 19:26) and as the final gift to humanity, Jesus gives Mary as a spiritual mother to us all: "Son, behold your mother" (cf. Jn 19:26). For this reason, Vatican II refers to Mary as a "mother to us in the order of grace " (Lumen Gentium, n. 62) and several twentieth century popes have officially taught the doctrine of Mary as Mediatrix of all graces, quoting the words of St Bernard:
"It is the will of God that we obtain all favours through Mary." The Mediatrix performs this task in intimate union with the Holy Spirit, the Sanctifier, with
whom she began the drama of our Lord's Redemption at the Annunciation (cf. Lk. 1:35).
