3 In the Garden of Gethsemane, where Jesus is in an agony; in the judgment-hall, where He is scourged, crowned with thorns, condemned to death, not there do we find Mary. But she knew beforehand all these agonies; she knew and saw them. When she professed herself the handmaid of the Lord for the mother's office, and when, at the foot of the altar, she offered up her whole self with her Child Jesus-then and thereafter she took her part in the laborious expiation made by her Son for the sins of the world. It is certain, therefore, that she suffered in the very depths of her soul with His most bitter sufferings and with His torments. Moreover, it was before the eyes of Mary that was to be finished the Divine Sacrifice for which she had borne and brought up the Victim. As we contemplate Him in the last and most piteous of those Mysteries, there stood by the Cross of Jesus His Mother, who, in a miracle of charity, so that she might receive us as her sons, offered generously to Divine Justice her own Son, and died in her heart with Him, stabbed with the sword of sorrow.
Source: Iucunda Semper Expectatione (Vatican.va)