Kierkeegard, a Protestant, speaks of Mary’s sorrow

“As Christ cries: My God, My God, why have you forsaken me - so must the Virgin Mary suffer the human analogue of this. A sword will pierce through your soul - and make manifest the thoughts of the hearts - yours, too, concerning whether you still are humble enough to believe that you are truly the chosen among women, who have found grace before God.” (S. Kierkegaard, Diary XI 1 A45) 

It was a Protestant brother who wrote these lines. If one of us had said it, it would have been considered excessive to declare that Mary on Calvary was pierced by a suffering which, humanly speaking, matched that of her Son. It is the truth, however, as long as we emphasize the adverb "humanly".

Father Raniero Cantalamessa (Preacher to the Papal Household)

In Mary: Mirror of the Church  (Adapted)