Wisdom in Prescribing Fasting
Sheikh al-Fawzan (ا الله) said: “Fasting contains the following wisdom:
it is education for the soul, purification from bad qualities and vicious disposition, as it narrows the path of penetration of the shaitan into the human body. And the shaitan penetrates into a person through his vessels. When he eats or drinks, his soul expands for passions, his intention weakens and his desire for worship diminishes. And fasting is the opposite of all this.
In fasting, alienation from the worldly and its passions, the desire for that world, the reason that prompts the sympathy (understanding) of the poor, the experience of their condition, since the fasting person tastes the feeling of hunger and thirst.
Fasting in Sharia is to abstain with intent (worship) from certain things like eating, drinking, intercourse, etc. from what is transmitted in the Sharia, also abstinence from profanity and impiety. “
See al-Mulyahhas al-fiqhi 1/374