The soul of each of us is a lamp. Now a lamp is wholly in darkness, even though it be filled with oil or tow or other combustible matter, until it receives fire and is kindled. So too the soul, though it may seem to be adorned with all virtues, yet does not receive the fire—in other words, has not received the divine nature and light—and is still unkindled and dark and its works are uncertain.

— Symeon the New Theologian, Discourses, 339.