Allah has made obligatory upon you the pilgrimage (hajj) to His sacred House which is the turning point for the people who go to it as beasts or pigeons go towards spring water. Allah the glorified made it a sign of their supplication before His Greatness and their acknowledgement of His Dignity. He selected from among His creation those who on listening to His call responded to it and testified His word. They stood in the position of His Prophets and resembled His angels who surround the Divine Throne securing all the benefits of performing His worship and hastening towards His promised forgiveness. Allah the glorified made it (His sacred House) an emblem for Islam and an object of respect for those who turn to it. He made obligatory its pilgrimage and laid down its claim for which He held you responsible to discharge it. Thus, Allah the glorified said:
". . . And (purely) for Allah, is incumbent upon mankind, the pilgrimage to the House, for those who can afford to journey thither. And whoever denieth then verily, Allah is Selfsufficiently independent of the worlds" (Qur'an, 3:96).
source : http://www.al-islam.org
