Mark the Ascetic - On the Spiritual Law 175-179

175. At a time of affliction, expect a provocation to sensual pleasure, for because it relieves the affliction it is readily welcomed.
176. Some call men intelligent because they have the power of discernment on the sensible plane. But the really intelligent people are those who control their own desires.
177. Until you have eradicated evil, do not obey your heart; for it will seek more of what it already contains within itself .
178. Just as some snakes live in glens and others in houses, so there are some passions which take shape in our thoughts while others express themselves in action. It is possible, however, for them to change from one type to the other.
179. When you find that some thought is disturbing you deeply in yourself and is breaking the stillness of your intellect with passion, you may be sure that it was your intellect which, taking the initiative, first activated this thought and placed it in your heart.