As an archer aims his arrow, the wise aim their restless thoughts, hard to aim, hard to restrain.
As a fish hooked and left on the sand thrashes about in agony, the mind being trained in meditation trembles all over, desperate to escape the hand of Mara the Tempter.
Hard it is to train the mind, which goes where it likes and does what it wants. But a trained mind brings health and happiness. The wise can direct their thoughts, subtle and elusive, wherever they choose: a trained mind brings health and happiness.
Those who can direct thoughts, which are unsubstantial and wander so aimlessly, are freed from the bonds of Mara.
They are not wise whose thoughts are not steady and minds not serene, who do not know dharma, the law of life. They are wise whose thoughts are steady and minds serene, unaffected by good and bad. They are awake and free from fear.
Remember, this body is like a fragile clay pot. Make your mind a fortress and conquer Mara with the weapon of wisdom. Guard your conquest always.
More than those who hate you, more than all your enemies, an untrained mind does greater harm. More than your mother, more than your father, more than all your family, a well-trained mind does greater good.
The Blessing of a Well-Trained Mind
The Dhammapada