In the Letters and in the Dialogue, her principal writings, Catherine of Siena describes the transformation that Christian faith and Baptism accomplish in the believer.  In one especially poetic passage, she writes to a knight-monk. His name was Nicholas di Strozzi, and he was a prior in one of the military orders that flourished during the Middle Ages. These knight-monks aimed to combine the virtues of chivalry with the ideals of self-discipline. To Prior Nicholas, then, Catherine writes:

Our King [she refers to Christ] behaves like a true knight who perseveres in battle until the enemies are defeated…. With unarmed hand, nailed fast to the cross, he defeated the prince of the world, with the wood of the holy cross as his mount. This knight of ours came armed with the breastplate of Mary’s flesh, flesh that bore the blows to make up for our wickedness. The helmet on his head is the painful crown of thorns, driven right into his brain. The sword at his side is the wound of his side, revealing to us the secret of his heart; it is a sword with a point of light that ought to pierce our inmost heart with the force of love. The staff in his hand is there in mockery. And the gloves on his hands and spurs on his feet are the scarlet wounds in the hands and feet of this gentle loving Word. 

What do we learn from this description of the suffering Christ? What does Catherine teach us about the transformation that brings the world stillness on Good Friday from noon until three o’clock? The answer is simple: We discover that because of his enormous love, Christ’s sufferings and Death cause the transformation of all that exists, the transformation we call Christian salvation. “What held him nailed firm and fast to the cross?” Catherine inquires. “Neither the nails nor the cross, which were not capable of holding the God-Man, but the bond of love for the Father’s honor and our salvation.”7 “What armed him?” Catherine further asks. Her answer: “Love.” The transformation that Catherine announces is one that creates in those persons who remain united with Christ a new ground for love, a new sort of loving. We call this freely bestowed transformation the gift of divine grace, both habitual and actual. The transformation affects both our persons and our actions.

Book: Compassionate Blood
Author: Catherine of Siena