At the Rue du Bac convent in Paris, the Virgin Mary appeared three times to Sister Catherine Labouré (1806-1876), between July and December 1830, in the community’s chapel, which became known as the Chapel of the Miraculous Medal.
A detail from the November 27, 1830, apparition is worth recalling:
It was the eve of the first Sunday of Advent, i.e the beginning of the liturgical year throughout which Christians are called to follow Christ through all the mysteries of his life.
Catherine noticed that Mary wore fifteen rings on each hand - three on each finger-, most of them resplendent and adorned with magnificent jewels, and some with little or no sparkle. Mary explained:
"'These represent the graces I bestow on those who ask me, and the jewels from which no rays emerge are the graces that people forget to ask me for."
Mary obtains from God, on our behalf, all the graces symbolized by the rays of light that radiate from her open hands, on the sole condition that we dare to ask for them, with the confidence, boldness and simplicity of a child. This is how Mary leads us to her divine Son.
The apparition did not explicitly ask for the Rosary to be prayed, but the number of her rings, three on each finger, definitely suggest the fifteen mysteries of the Rosary, since until recently, it consisted of 15 mysteries and was often prayed on a one-decade rosary, a ring covered with ten beads to count the Hail Marys.
This detail might have been a discreet indication that the best way to ask for graces is to pray the Rosary, that is, to contemplate the life of Christ with Mary's eyes, to make our requests to Christ with Mary, to let ourselves be transfigured by Christ, and to proclaim Christ with Mary.
F. Breynaert
Marian Encyclopedia