Imam Khomeini, the late founder of the Islamic Republic through a series of theological works stressed the need of protecting the worships against the intrusion of Satan.
According to Imam, one of the important cordial disciplines of the Salat and other worships which is of the chief cordial disciplines, and to implement it is one of the great affairs and minute problems, is protecting the worships against the intrusion of Satan. The noble āyah:
“And those who keep guard on their Salats”
Probably refers to all degrees of keeping guard, a degree of which, or rather the most important one of them, is to guard against Satan's intrusion.
To go into details, we say that it is quite explicit to the people of knowledge and the men of heart that as bodies require material food for nourishment, and that the food should be suitable for their disposition so that they may be brought up corporeally and have vegetable growth, similarly the hearts and the souls require a particular food to suit them both, so that they may be educated with it, and feed on it to grow up spiritually and progress inwardly.
The nutrition suitable for the growth [nash'ah] of the souls is the divine knowledge [ma'ārif] from the beginning of existence till the ultimate end of the system of existence. It is expressed in defining philosophy by the great experts that: “It is man's development into a mental world matching the material world in its form and perfection.”
This is an indication of the said spiritual nutrition, as the hearts feed on spiritual merits and divine rites.
It must be noted that each one of these foods, if kept away from Satan's intrusion and prepared by the hands of the guardianship of the Seal of the Prophets and Allah's great friend (PBUH), the soul and the heart would be nourished by them and would attain the perfection becoming of humanity and ascend to the proximity of Allah.