Holy

After describing true devotion to Jesus through Mary as interior and tender, he writes that the third characteristic of the devotion is that it is holy:

True devotion to Our Lady is holy; that is to say, it leads the soul to avoid sin and to imitate the virtues of the Blessed Virgin, particularly her profound humility, her lively faith, her blind obedience, her continual prayer, her universal mortification, her divine purity, her ardent charity, her heroic patience, her angelic sweetness and her divine wisdom. These are the ten principal virtues of the most holy Virgin.
​- True Devotion, 108

Our Lady is the model of all virtues and we are called to imitate her as far as our limited capacity permits. She is also treasurer - as our tender Mother, she shares with us her virtues. Her virtues are her gift to the soul that gives itself entirely to her care. The more generous we are in serving Jesus and Mary, the more generous the gifts we receive!

Jesus, our great friend, has given Himself to us without reserve, body and soul, virtues, graces, and merits. Se toto totum me comparavit, said St. Bernard,—”He has bought the whole of me by the whole of Himself.” Is it not, then, a simple matter of justice and of gratitude that we should give Him all that we can give Him?
St. Louis Marie de Montfort