A thought is an upshot of the desire. When someone thinks about what he wants, he does not think of something undesirable. For example, a person never thinks about the day of his death. On the contrary, he will always contemplate his perpetuity, for this is his desire. Thus, one always thinks of what is desirable (...) It turns out that thought serves desire, and desire is the self of the person. Now, there is a great self, or a small self. A great self dominates the small selves. He who is a small self has no dominion whatsoever, and the advice is to magnify the self through the diligence of the thought on the desire, since it grows to the extent that one thinks of it.