60 There is but one Mediator as we know from the words of the apostle, "for there is one God and one mediator of God and men, the man Christ Jesus, who gave himself a redemption for all". The maternal duty of Mary toward men in no wise obscures or diminishes this unique mediation of Christ, but rather shows His power. For all the salvific influence of the Blessed Virgin on men originates, not from some inner necessity, but from the divine pleasure. It flows forth from the superabundance of the merits of Christ, rests on His mediation, depends entirely on it and draws all its power from it. In no way does it impede, but rather does it foster the immediate union of the faithful with Christ.
Source: Lumen Gentium (Vatican.va)