Associated with our physical heart is our spiritual heart. The heart is sometimes called the spirit. The heart is at the center of the human being. Therefore, the darkening of the heart is at the center of our sickness.
The heart is often called the spiritual intellect (which is different from the rational intellect). With our rational minds we can perform academic work, conduct scientific study, and develop philosophical concepts about God, human beings, and the universe, but with the heart we know God directly by experience.
I do not know my wife through academic study, objective observation, or rational reflection. If I did only know her in this manner, I would know information about my wife, but I would not really know her. Rather, I know my wife personally as my own wife. We know each other through the experience of being married together and raising our children together in our home. According to the Orthodox Way, a true theologian is not a scholar who has studied philosophical doctrines about God based on academic study, observation, and rational reflection, but a true theologian is one who knows God with the heart by experience through prayer.
The heart is the eye of the soul by which we see the spiritual reality. Because our hearts are darkened, we do not see (that is, we do not know by experience) the true God as we should. The blackness of our hearts prevents the healing, transformative Grace from penetrating into our souls. We do not love as we should. We are blind to the fullness of reality. We do not see ourselves honestly, nor do we see others as they truly are, fellow human beings made according to the image of God.
Again, since the heart is the center of the human being, the darkening of the heart is central to our illness.
Text copyright © 2017 by Fr. Symeon D. S. Kees