The Philosophy of Hajj from the Perspective of Imam Ali (a.s.)
Imam Ali (a.s.) says: See that Allah, the Exalted, tested people from the time of Adam (a.s.) until the end of the world with stones that neither benefit nor harm, nor see nor hear, and made those stones a house with His sanctity and made it a place for people to gather. Then He placed it in the most rocky places and the most barren parts of the earth and the narrowest valleys, among rough mountains and hot sands and shallow springs and distant settlements, where no camel, horse, cow or sheep would fatten. Then Allah commanded Adam and his children to turn towards it. So, the Sacred House became their destination and their landing place. People turn to it with all their might from distant plateaus and plains, from deep valleys and steep ravines, and from the scattered islands of the seas, to shake their shoulders from their humiliation and filth, and to walk around it with disheveled hair and dusty bodies, saying, "There is no god but Allah." They cast aside their personal garments and put on the clothes of Ihram instead, changing their beautiful appearance by not straightening their hair. This is a great test, a severe trial, a clear trial, and an effective purification and cleansing that God Almighty has made a cause of His mercy and reaching His Paradise.
If God, the Exalted, had willed, He would have placed His Sacred House and His Noble Shrines amidst gardens and streams and flat lands, full of trees and fruits, whose houses are connected to each other and whose settlements are close to each other, amidst wheat fields and orchards and fields full of plants and plains full of water, amidst orchards and orchards full of pleasure and well-developed roads, and then, in proportion as the test and trial were easier, the reward and punishment would have been less. If the foundation of the Kaaba and the stones used in its construction had been of green emeralds and red rubies and with light and brightness, it would have reduced the penetration of doubt and hesitation in the breasts [of those who see the outward] and would have removed the efforts of Satan from the hearts and removed the turbulence of doubt and temptation from the people. But God tests His servants with various hardships, enslaves them with various struggles, and tests them with various afflictions, in order to remove arrogance and self-importance from their hearts, instill humility and modesty in their souls, open the doors of His grace and mercy to them, and make the means of His forgiveness easily available to them.