From Alan Moorehead's The White Nile:
Perhaps it is the very austerity of life in these arid wastes that predisposes the people to worship. Mecca lies only a short journey away across the Red Sea, and the Prophet Mohammed himself lived and received his inspirations in just such an environment as this. An immense silence possesses the surrounding desert. The heat is so great it stifles the appetite and induces a feeling of trance-like detachment in which monotony dissolves into a natural timelessness, visions take on the appearance of reality, and asceticism can become a religious object of itself.
These are the ideal circumstances for fanaticism, and a religious leader can arouse his followers with a devastating effect. All at once the barriers are swept aside, revolt becomes a holy duty, and it can be a shocking and uprooting thing because it makes so sharp a break with the apathy that has gone before. The long silence is broken, the vision is suddenly translated into action, and detachment is replaced by a fierce and violent concentration.
Tags: Alan Moorehead, The White Nile