An 8th sword piercing Mary’s heart

A certain youth practiced the devotion of visiting every day an image of the sorrowful Mary, in which she was represented with seven swords piercing her heart.

One night the unhappy youth fell into mortal sin. Going next morning to visit the image, he saw in the heart of the blessed Virgin not only seven, but eight swords.

As he stood gazing at this, he heard a voice saying to him, that this sin had added the eighth sword to the heart of Mary. This softened his hard heart; he went immediately to confession, and through the intercession of his Advocate, recovered the divine grace. 

Saint Alphonsus Liguori, The Glories of Mary