The fact that Mary, for example, is present at the foot of the cross means that she is associated, in the very act of Redemption, to the sacrifice of Christ by the expressed will of the Saviour who says to her “Woman, here is your son,” (Jn, 19:27) The Saviour asks of her to consent to his own sacrifice, and thus to his death, and in exchange for the acceptance of the death of her son-- which is Mary’s sacrifice—the mother of Christ is brought to accept humanity, symbolized by John, as her new son.
--Cardinal Marc Ouellet, Actualité et avenir du Concile oecuménique Vatican II