From Jesus, of course, we receive grace as its author, and from Mary as its mediator; from Jesus as Savior, from Mary as advocate; from Jesus as the source of grace, from Mary as its channel.
Jesus as the source of grace, Mary as its channel.
St. Bernard says that God constituted Mary as an aqueduct of the mercies that he wanted to bestow on men; therefore he filled her with graces, so that from her fullness his share would be communicated to each one. For this reason, the saint exhorts us to consider with how much love God wants us to love this exceptional Virgin, for in her he has placed all the treasures of his goods, and thus, whatever we have of hope, grace and salvation, we should thank our beloved queen for everything comes to us from her hands and through her intercession. These are her beautiful words: "See with what affection and devotion he desires us to honor her, he who placed all the fullness of good things in Mary, for all that we have in us of grace and salvation, let us understand that it comes to us from her".
Unhappy is he who closes to himself this channel of grace by not entrusting himself to Mary! Olofernes, when he wanted to take over the city of Bethulia, ordered to occupy the aqueducts of the city (Jdt 7:7). This is what the devil does when he tries to take possession of a soul: he makes it abandon its devotion to Mary Most Holy. Once this channel is closed, she will easily lose the light, the fear of God, and finally, eternal salvation.
The Glories of Mary - St. Alphonsus