The notion of Mary Mediatrix is still debated today. Yet it has a strong tradition to support it. Leo XIII, in his Octobri Mense encyclical of September 22, 1891, declared: "It may be affirmed that, by the will of God, Mary is the intermediary through whom is distributed unto us this immense treasure of mercies gathered by God, for mercy and truth were created by Jesus Christ. Thus as no man goes to the Father but by the Son, so no man goes to Christ but by His Mother."
And Pius XI in the conclusion of the encyclical Miserentissimus Redemptor said: "Christ, the only mediator between God and men, chose to associate his Mother as the advocate of sinners and as the dispenser and mediatrix of his grace."
Until his crucifixion, Christ was the sole dispenser of all his gifts. But after his crucifixion, he was pleased to entrust his Mother with a wonderful power, that of dispensing to his children on earth all the graces necessary to convert and persevere in doing good.
This is why the devotion to the Sacred Heart and the devotion to the Immaculate Heart of Mary cannot be dissociated. Fatima fulfils Paray-le-Monial.
Yves de Lassus
Centenary of Fatima
Letter of Liaison n. 53 (June 14, 2017)