A lot of religions talk about the Devil or the evil ones who exist inside and outside us. Buddhism also talks about the personification of evil or Mara in its mythology. Human beings all have Mara in their heart. Desire always affects people’s will and morality, interfering with practicing the way to Buddhahood. One Chinese maxim says it thus; “the virtuous rise one foot, the wicked ten feet.” Sakyamuni’s way of practicing led him to subdued Mara making it possible for him to reach enlightenment and become Buddha…

Under the Bodhi tree Siddhartha sat in contemplation, the thread of his thoughts becoming increasingly clear. His goal during the last six years of serious practice was to eliminate various kinds desire. He had practiced self-torture, letting his body incur the most painful deprivations, with the hope that this way would free him from desire. Then he practiced meditation; certain this was the surest way to purification and gaining mind-control. But no matter what he did he still couldn’t find the way to release his mind.
Sakyamuni started to question; “Is it possible to destroy desire?” The wind wafted through the tree’s leaves but Siddhartha sat still, quiet and thinking. “Man’s body, with its five senses, naturally has desire. Desire is one part of life.” He continued “With death desire stops. But if this is the only way, why continue to practice? I should just kill myself.” He paused; “Is desire our enemy? All people have desire. If you know how to separate temptation from desire and see that the essence of desire is empty, then desire can help you chase the truth.”
(Here is an example of the emptiness of desire. When you desire something it first arises in your mind, there is no action. This desire is empty until you act on it/allow it to affect you. Then once you have acted on it, the desire is gone…emptiness once again.)
Sakyamuni’s thoughts continued; “Mara, manifested as desire, is one part of my mind. Mara is also my partner in seeking truth.” Now Sakyamuni understood. (He could make desire be a horse that would bring him where he wanted to go.)

So desire can be good for both our society and personal progress. It can give us the power of motivation… but it can also be a devil. Desire can control our mind and body and sink our lives into an abyss of suffering. The outcome relies entirely upon you how to treat your desire.