In one part of his speeches, professor Hussein Ansarian said: at times, the divine prophets used to say to nations: " You are ignorant people" (AL-NAML (THE ANT), verse 55), your intellect is dead; sometimes, they used to say: " you are like animals" and your soul is dead; and sometimes the lord of the universe would say to the nations: " your hearts turned as hard as rocks" AL-BAQARA (THE COW), verse, 74), you have developed a stone-like hearts and they are not influenced because you have only fed your stomach, but you have not given your intellect any foods. These divine teachings and facts are the food of intellect. We must not leave our intellects, souls and hearts unfed for more than a week. We can read a good book or listen to a good and informative lecture, such things revive the mankind's soul and intellect as well as their heart.
source : erfan.ir