For St. Catherine, the merciful love of God so essentially defines who He is that, along with St. Augustine and St. Thomas, Catherine understands that it is precisely despair of His mercy that constitutes the only unforgivable sin.
The Church calls on us all to pursue the New Evangelization in order to establish a Culture of Life that will lead to the advent of a Civilization of Love.
We will not presume to outline here the whole teaching of St. Catherine's masterpiece, The Dialogue. Rather we will focus on the theme of Divine Mercy as it appears in the book.
When we fail to be merciful, St. Thomas reassures us that Divine Mercy for the repentant is not just adequate or sufficient for us, but superabundant, as infinite as God's nature itself.
In order to understand St. Thomas Aquinas' theory of atonement, we need to be clear about what he meant in saying that Jesus Christ makes "satisfaction" for our sins.
Week 20: According to St. Thomas Aquinas, the supreme manifestation of God's Mercy is the sending of His divine Son into the world to share our human nature, and to make "atonement" or "satisfaction" for our sins, meriting for us superabundant graces of regeneration and sanctification.
What, then, is the mercy of God, according to St. Thomas? It cannot be an emotion or a passion, since God in His infinite, immutable perfection cannot be subject to changing passions that "happen" to Him or "overcome" Him, or that reduce His fullness of Being in any way.
Saint Thomas Aquinas (1225-1274) defined the virtue of "mercy" in his great Summa Theologiae as "the compassion in our hearts for another person's misery, a compassion which drives us to do what we can to help him."