We acclaim her as “Mother of mercy, our life, our sweetness, and our hope.” The Blessed Mother also gives us one of the greatest songs of the Judeo-Christian tradition. Mercy is at the heart of the Magnificat, and that eternal mercy was carried in her womb:
These words of the Church at Easter re-echo in the fullness of their prophetic content the words that Mary uttered during her visit to Elizabeth, the wife of Zechariah: “His mercy is…from generation to generation.”(Lk. 1:50) At the very moment of the Incarnation, these words open up a new perspective of salvation history. After the resurrection of Christ, this perspective is new on both the historical and the eschatological level. From that time onwards there is a succession of new generations of individuals in the immense human family, in ever-increasing dimensions; there is also a succession of new generations of the People of God, marked with the Sign of the Cross and of the resurrection and “sealed”(Cf. 2 Cor. 1:21-22) with the sign of the Paschal Mystery of Christ, the absolute revelation of the mercy that Mary proclaimed on the threshold of her kinswoman’s house: “His mercy is…from generation to generation.”(Lk. 1:50)
This is an important reminder: from our devotional prayer, from the Scriptures, as well as the image of the incarnation as the embodiment of God’s eternal mercy.
Dives in Misericordia, the second encyclical of Pope John Paul II, is available online here, and is copyright © 1980 – Libreria Editrice Vaticana
Catholic Sensibility 
One of the loveliest pieces of Western sacred art is the Ravensburger Schutzmantelmadonna by Michael Erhart circa 1480:
http://www.wikigallery.org/wiki/painting_77992/Michael-Erhart/Ravensburg-Madonna-of-Mercy
And this reminds me of my love for the medium of wooden sculpture and wish we had more of it nowadays. Like this late Gothic masterpiece from a generation after the Ravensburger Madonna, the Holy Blood Altarpiece in St Jakob’s in Rothenberg ob der Tauber: