Marcus Aurelius
Author: Marcus Aurelius
Publisher: Penguin Great Ideas (2005)

There are four aberrations of your soul's helmsman which you must constantly guard against, and suppress whenever detected. Say to them one by one, 'This is a thought which is not necessary,' 'This is one which would undermine fellowship,' This is not the voice of my true self' (for to speak anything but your true sentiments, remember, is of all things the most misplaced), and, fourthly, when you are tempted into self-reproach, 'This would prove the divine element in me to have been discomfited and forced to its knees by the ignoble and perishable flesh with its gross conceptions.