The heart is the seat of the passions, the raw, blazing energies that mediate between the reason and the appetite, enforcing the will of one or the other, according to how they are trained. We perceive goodness with the reason, but we feel it in the heart.
As C.S. Lewis said, we moderns are, in large part, ‘men without chest’, men whose capacity for passion, whose driving desire for the high and good and beautiful has atrophied. And if not atrophied, then become inflamed and warped and divorced from our crippled reason, so that our passions strike out blindly and thoughtlessly at the behest of the appetites. In a well-ordered soul, the passions are akin to a disciplined and chivalrous force of loyal vassals grouped around the king. In a disordered soul, they are violent and selfish brigands, grasping at any plunder they can find. And in a modern soul, they’re something like Antifa; violent, ignorant thugs animated by forces they don’t understand and only possessing the strength and courage to strike at those weaker than themselves.
Leave our unhappy circumstance for the moment, though, and consider the Sacred Heart of Jesus; the blazing, consuming fire of passion that radiates from a heart of pure love. He who made the world and called it good, who knows goodness as no other heart can, what a terrible, masculine blaze of energy and delight must there be!
But the Sacred Heart is shown surrounded by the Crown of Thorns. Imagine, if you can, the sensation of the heart beating against the thorns, straining through the piercing wounds, pushing outwards in the expansive force of its love. For love, the perception and reaction to goodness, must always come with pain in a fallen world, since the goodness of creation is marred and broken. The more one loves, the more it hurts to see flaws in the thing one loves, and more still it hurts to see that thing injured or subjected to violence.
A real, strong, disciplined passion will be a source of grief and pain. The more purely we love, the more we will suffer on account of that love. God grant us hearts strong enough to love passionately, and courageous enough to suffer for it.