Here are some good thoughts of JPII on mercy and forgiveness:
Society can become ever more human only if we introduce into the many-sided setting of interpersonal and social relationships, not merely justice, but also that “merciful love” which constitutes the messianic message of the Gospel.
… Forgiveness demonstrates the presence in the world of the love which is more powerful than sin. Forgiveness is also the fundamental condition for reconciliation, not only in the relationship of God with man, but also in relationships between people. A world from which forgiveness was eliminated would be nothing but a world of cold and unfeeling justice, in the name of which each person would claim his or her own rights vis-à-vis others; the various kinds of selfishness latent in man would transform life and human society into a system of oppression of the weak by the strong, or into an arena of permanent strife between one group or another.
For this reason, the Church must consider it one of her principal duties – at every stage of history and especially in our modern age – to proclaim and to introduce into life the mystery of mercy, supremely revealed in Jesus Christ. Not only for the Church herself as a community of believers but also in a certain sense for all of humanity, this mystery is the source of a life different from the life which can be built by men.
From the November, 1980 encyclical letter “Dives in Misericordia” or “On the Mercy of God.”
The image above is from here.
Anniversary Hat-tip: Rocco