Imam Ali (AS) said, The mainstay of this world is by four [groups]: A scholar who acts on his knowledge, an ignorant person who is not too proud to learn, a wealthy person who is generous with his wealth to the needy and a poor person who does not sell his Hereafter for his worldly life. So when the scholar does not act on his knowledge, the ignorant one refuses to learn; and when the wealthy is miserly with his wealth, the poor one sells his Hereafter for his world.