Why the Sorrowful Mother? Why do Catholics honor Mary, the Mother of God with the title of "Sorrows"? Is it an honor to be called such? Some good questions, I think. Mark Miravalle answers the question this way:
We could just as well ask St. Paul why he instructs all Christians to "make up what is lacking in the sufferings of Christ for the sake of his body, which is the Church" (Colossians 1:24).
We Christians, too, will suffer and do suffer. Our suffering has the capacity to release a portion of the infinite graces merited by Jesus at Calvary, what theologians call "objective redemption." But as these redemptive graces of Jesus must be personally received by the human heart, every Christian has a role in this mysterious release and reception of grace which theologians call "subjective redemption."
Mary alone, as the "New Eve" with Jesus the "New Adam," participates in both objective and subjective redemption: both in the historic acquisition of redemptive grace and in the providential release of redemptive grace. Blessed John Paul would teach of his mother and ours that Mary's intensity of suffering at Calvary was a "contribution to the redemption of all" (Salvifici Doloris, 25).