This is what I have heard. “Monks, in the Himalaya, king of mountains, there are inaccessible and rugged places where neither monkeys nor human beings roam. In the Himalaya, king of mountains, there is inaccessible and rugged country where monkeys roam, but not human beings. In the Himalaya, king of mountains, there are level parts which are delightful where both monkeys and human beings roam. There hunters spread monkey lime along the trails of the monkeys in order to trap them. Now those monkeys who are by nature not so foolish, not so impulsive, see the lime and pass round it, keeping their distance. But a monkey who is foolish and impulsive comes up to the lime and grasps it with its paw; then he is trapped by his paw. Thinking that he can free his paw, he grasps the lime with his second paw. Then he is trapped by that. Thinking that he can free both his paws, he grasps the lime with his foot. Then he is trapped by that. Thinking that he can free both his paws and also his foot, he grasps the lime with his second foot. Then he is trapped by that. Thinking that he can free both his paws and both his feet, he grasps the lime with his muzzle. Then he is trapped by that. So, monks, caught at five points, the monkey lies there screeching. He has met with ruin and disaster, and the hunter will do whatever he wants with him. The hunter spears him and, fastening him to that same piece of wood, goes to where he wants. Monks, this is what happens when one strays beyond one’s own range into the territory of others.

“Therefore, monks, do not stray beyond your own range into the territory of others. Mara, the Bad One, will find a way of getting to those who stray beyond their own range into the territory of others; he will get a hold on them. So what, monks, is not the range of a monk, but the territory of others? It is the five kinds of object of sense desire. Which five? Visible forms experienced through the eye that are desirable, attractive, agreeable, pleasing, seductive, appealing; sounds experienced through the ear; smells experienced through the nose; tastes experienced through the tongue; the objects of touch experienced through the body that are desirable, attractive, agreeable, pleasing, seductive, appealing. These are not the range of a monk, but the territory of others.

“You should keep to your range, your own accepted territory, monks. Mara will not find a way of getting to those who keep to their range, their own accepted territory; he will not get a hold on them. So what is your range, your own accepted range? The four ways of establishing mindfulness. Which four? Here a monk lives watching the body as body; he is determined, fully aware, mindful, overcoming his longing for and discontent with the world. He lives watching feelings as feelings; he is determined, fully aware, mindful, overcoming his longing for and discontent with the world. He lives watching mind as mind; he is determined, fully aware, mindful, overcoming his longing for and discontent with the world. He lives watching qualities as qualities; he is determined, fully aware, mindful, overcoming his longing for and discontent with the world.”

From Sayings of the Buddha: A Selection of Suttas from the Pali Nikayas, translated by Rupert Gethin, Oxford: Oxford University Press, 2008, pp. 232-233.