Teachings of Seraphim
Part 17. Sorrow
When the evil spirit of sorrow seizes the soul, then, by filling it with bitterness and unpleasantness, it does not allow it to pray with necessary diligence; it disrupts the attention necessary for reading spiritual writings, deprives it of humility and good nature in the treatment of others and breeds aversion to any discussion.
For the sorrowful soul, by becoming as if insane and frenzied, can neither accept kind advice calmly, nor answer posed questions meekly. It runs from people as if from the perpetrators of its embarrassment, not understanding that the reason for its illness — is within it. Sorrow is the worm of the heart, gnawing at the mother that bore it.
He who has conquered passions has also defeated sorrow. But one overcome by passions will not avoid the shackles of sorrow. As an ill person can be identified by the color of his face, so is one overcome by passions distinguished by sorrow.
It is impossible for one who loves the world not to feel sorrow. But he who despises the world is always cheerful. As fire purifies gold, so sorrow in God -- penitence -- purifies the sinful heart.