Rev. Joseph I. Dirvin, C.M., was a priest and author of the twentieth century who served at St. John’s University, New York. In his book Saint Catherine Labouré of the Miraculous Medal (available on vincentians.com), he wrote:
The high point of Catherine’s life was… the great apparitions of the Virgin Mary. For these was she born, for these came she into the world, even as Christ came to bear witness to the truth. They are the reason for her being and the wellspring of her holiness. The years of sanctity that went before them, the years of sanctity that followed after, cluster about them like a setting about a gem. Not that Catherine Labouré was holy because she saw the Blessed Virgin; she was holy because she was faithful to the mission given her to do. God’s plan for her life and sanctification was: that she should cultivate a deep devotion to the Mother of God; that she should receive, at first hand, important instructions from this great Lady; that she should carry out these instructions to the letter; and, while doing all this, she should remain hidden, living an ordinary religious life in doing ordinary religious works.
All the graces given her by God worked to this end. Catherine corresponded to every grace; she did what was expected of her and did it well. This is why she is a saint.
A history of the Apparitions of the Virgin Mary to St. Catherine Labouré can be found on the website of the International Miraculous Medal Association.
Take a look inside the Chapel of the Miraculous Medal at the Daughters of Charity Motherhouse in Paris, France, where the apparitions took place. Narrated by Sister Denise LaRock, D.C.