The Struggle of Man 20:54
Eat and allow your cattle, cows, camels, goats, and sheep to graze on the grass and vegetation.
In this are the symbols of Allah’s favor to the people who are discerning, intelligent and conscious. They are companions of one another and their intelligence prohibits them from shameful deeds.
Like for the cattle, grass should be available to everyone because it represents common knowledge. However, this common knowledge is only given to the priest class and the clergy. This leaves the common man to struggle to keep his senses, intelligence and spiritual makeup together so that he is not at the mercy of those with the common knowledge.