By means of the worldly knowledge given to them by Allah, these nations were able to bring into their submission the forces of nature which are under the charge of the angels. This amazing progress was, however, not enough to save them from the incitement of the devil, and they got involved in evil and obscene behavior, the like of which is not found in the history of mankind. Their salvation now lies in the Holy Quran. This is the only Book in which the revelation which saved Adam and Eve has reached its perfection, and is safeguarded in its original form. The fear and sadness that is created by evil action can only be removed by following the guidance given through Divine revelation.
Fear is generated before the commission of an act, sadness follows it.
For example, when somebody tells a lie, fear is generated in his heart that it may be discovered, and when it is, sadness follows. Freedom from fear and sorrow is the serenity of mind, or the paradise of the heart. When the soul of a believer carries with him to the life Hereafter, this spiritual or inner paradise, he is rewarded therein the external paradise of the Hereafter. This is the message of complete satisfaction and happiness of internal and external paradise that the Holy Quran gives mankind as the purpose of its revelation. Without inner serenity, the external gardens and means of comfort become a thorn in one s side.