Just as in every world tradition, there is a heart teaching or esoteric aspect of Islam. The most widely known is the Sufi tradition, and the brilliant mystical poet Rumi.
Let the body needs dwindle and the souls decisions increase.
Diminish what you give your physical self.
Your spiritual eye will open.
Listen to the prophets, not to some adolescent boy.
The foundation and the walls of the spiritual life
are made of self-denials and disciplines.
-Rumi, Muhammed and the Huge Eater
"In these studies of Kabbalah, we need to be practical; there are authors who write marvels, but when one looks at them, one realizes that they have not lived what they have written; they did not experience it in themselves, and that is why they are mistaken. I understand that one must write what one has directly experienced by oneself. I have proceeded in this way for my part."