"Suppose, monks, a man catches six animals of different domains and different resorts of living — a snake, a crocodile, a bird, a dog, a jackal and a monkey, tethering each with a stout rope. Having tethered them with a stout rope, he fastens the ropes together in the middle, he lets go of them. Now, monks, these six animals of different domains and feeding habits would swing around and struggle, each trying to get to his natural domain. The snake would struggle, thinking 'I'll get to the ant-hill'; the crocodile: 'I'll get into the water'; the bird: 'I'll fly up in the air'' the dog: 'I'll make for the village'; the jackal: 'I'll make for the charnel-ground'; the monkey: 'I'll head for the forest.'
"Now, monks, when those six hungry animals grew weary, they would yield to the one that was the strongest, go his way and be under his power. In the same way, monks, whenever a monk fails to practice and develop mindfulness as to body, the eye struggles to draw him towards attractive objects, while unattractive objects are repellent to him... The mind struggles to draw him towards attractive objects of thought, while unattractive objects of thought are repellent to him. This, monks, is lack of restraint. And what, monks, is restraint? In this, a monk, seeing objects with the eye, is not drawn to attractive objects, is not repelled by unattractive objects. He remains with firmly established mindfulness as to body, his mind being unrestricted.[1] He knows in truth that liberation of the heart, that liberation by wisdom,[2] through which those evil, unskilled states that have arisen pass away without remainder...
"Suppose a man catches six animals (as before), and he fastens the rope together to a stout post or pillar... Then, when those six animals grow weary, they would have to stand, crouch or lie down by the stout post or pillar. In the same way, monks, when a monk practices and develops mindfulness as to the body, the eye does not struggle to draw him towards attractive visual objects, nor are unattractive visual objects repellent to him... the mind does not struggle to draw him towards attractive objects of thought, nor are unattractive objects of thought repellent to him. This, monks, is restraint.
"'Tethered to a stout post or pillar,' monks, denotes mindfulness as to body. Therefore, monks, this is how you must train yourselves: 'We shall practice mindfulness as to body, develop it, make it our vehicle, our dwelling-place, our resort, we will build it up and undertake it thoroughly.' This, monks, is how you must train yourselves."