and Simeon blessed them, and said to Mary, his mother, "Behold, this child is set for the falling and the rising of many in Israel, and for a sign which is spoken against.
And so he is telling Mary, "Look, this child is set for great blessings to the people, but it's going to pierce as a sword through your own soul." Preparing her for the agony and the pain that she would experience, as she would watch one day this child, hanging on the cross.