[1] Card game: A playing card of special value that can substitute for other cards. 

[2] Figuratively: A person or thing of special value that can be used at a particular time. 

In India, fools are equated with saints because they live in the innocence of childhood. If the fool gets lost in the waves of the grass, it is only because he experiences things so directly that he loses sight of the big picture. If he gets lost in the rays of the sun, it is only because he is completely absorbed in what he sees. 

If he forgets himself in the chirping of the birds, it is only because he is causally part of it, because the same song is playing inside him. The Fool may not be a good fighter in the struggle for power and prestige, but he already possesses the greatest treasure: purity of heart. 

If you have drawn this card, it is all about direction: Is the fulfillment of your plans your goal? Is the fulfillment of your desires your happiness? What is truly important to you? Who or what are you serving? Where do you look for your treasure?