http://www.accesstoinsight.org/tipitaka/mn/mn.138.than.html
I have heard that on one occasion the Blessed One was staying near Savatthi in Jeta's Grove, Anathapindika's monastery. There he addressed the monks: "Monks!"
"Yes, lord," the monks replied.
The Blessed One said: "Monks, I will teach you a statement & its analysis. Listen & pay close attention. I will speak."
"As you say, lord," the monks responded.
The Blessed One said this: "A monk should investigate in such a way that, his consciousness neither externally scattered & diffused, nor internally positioned, he would from lack of clinging/sustenance be unagitated. When — his consciousness neither externally scattered & diffused, nor internally positioned — from lack of clinging/sustenance he would be unagitated, there is no seed for the conditions of future birth, aging, death, or stress."
That is what the Blessed One said. Having said it, the One Well-gone got up from his seat and went into his dwelling.
Then, not long after the Blessed One had left, this thought occurred to the monks: "This brief statement the Blessed One has made, after which he went into his dwelling without analyzing the detailed meaning — i.e., 'A monk should investigate in such a way that, his consciousness neither externally scattered & diffused, nor internally positioned, he would from lack of clinging/sustenance be unagitated. When — his consciousness neither externally scattered & diffused, nor internally positioned — from lack of clinging/sustenance he would be unagitated, there is no seed for the conditions of future birth, aging, death, or stress': now who might analyze the unanalyzed detailed meaning of this brief statement?" Then the thought occurred to them, "Ven. Maha Kaccana is praised by the Teacher and esteemed by his knowledgeable companions in the holy life. He is capable of analyzing the unanalyzed detailed meaning of this brief statement. Suppose we were to go to him and, on arrival, question him about this matter."
So the monks went to Ven. Maha Kaccana and, on arrival exchanged courteous greetings with him. After an exchange of friendly greetings & courtesies, they sat to one side. As they were standing there, they [told him what had happened, and added,] "Analyze the meaning, Ven. Maha Kaccana!"
[He replied:] "Friends, it's as if a man needing heartwood, looking for heartwood, wandering in search of heartwood — passing over the root & trunk of a standing tree possessing heartwood — were to imagine that heartwood should be looked for among its branches & leaves. So it is with you, who — having bypassed the Blessed One when you were face to face with him, the Teacher — imagine that I should be asked about this matter. For knowing, the Blessed One knows; seeing, he sees. He is the Eye, he is Knowledge, he is Dhamma, he is Brahma. He is the speaker, the proclaimer, the elucidator of meaning, the giver of the Deathless, the lord of the Dhamma, the Tathagata. That was the time when you should have questioned him about this matter. However he answered, that was how you should have remembered it."
"Yes, friend Kaccana: knowing, the Blessed One knows; seeing, he sees. He is the Eye, he is Knowledge, he is Dhamma, he is Brahma. He is the speaker, the proclaimer, the elucidator of meaning, the giver of the Deathless, the lord of the Dhamma, the Tathagata. That was the time when we should have questioned him about this matter. However he answered, that was how we should have remembered it. But you are praised by the Teacher and esteemed by your knowledgeable companions in the holy life. You are capable of analyzing the unanalyzed detailed meaning of this brief statement. Analyze the meaning, Ven. Maha Kaccana!"
"In that case, my friends, listen & pay close attention. I will speak."
"As you say, friend," the monks responded.
Ven. Maha Kaccana said this: "Concerning the brief statement the Blessed One made, after which he entered his dwelling without analyzing the detailed meaning — i.e., 'A monk should investigate in such a way that, his consciousness neither externally scattered & diffused, nor internally positioned, he would from lack of clinging/sustenance be unagitated. When — his consciousness neither externally scattered & diffused, nor internally positioned — from lack of clinging/sustenance he would be unagitated, there is no seed for the conditions of future birth, aging, death, or stress' — I understand the detailed meaning to be this:
"How is consciousness said to be scattered & diffused? There is the case where a form is seen with the eye, and consciousness follows the drift of (lit.: 'flows after') the theme of the form, is tied to the attraction of the theme of the form, is chained to the attraction of the theme of the form, is fettered & joined to the attraction of the theme of the form: Consciousness is said to be externally scattered & diffused.
"There is the case where a sound is heard with the ear... an aroma is smelled with the nose... a flavor is tasted with the tongue... a tactile sensation is felt with the body... an idea is cognized with the intellect, and consciousness follows the drift of the theme of the idea, is tied to the attraction of the theme of the idea, is chained to the attraction of the theme of the idea, is fettered & joined to the attraction of the theme of the idea: Consciousness is said to be externally scattered & diffused.
"And how is consciousness said not to be externally scattered & diffused? There is the case where a form is seen with the eye, and consciousness does not follow the drift of the theme of the form, is not tied to... chained to... fettered, or joined to the attraction of the theme of the form: Consciousness is said not to be externally scattered & diffused.
"There is the case where a sound is heard with the ear... an aroma is smelled with the nose... a flavor is tasted with the tongue... a tactile sensation is felt with the body... an idea is cognized with the intellect, and consciousness does not follow the drift of the theme of the idea, is not tied to... chained to... fettered, or joined to the attraction of the theme of the idea: Consciousness is said not to be externally scattered & diffused.
"And how is the mind said to be internally positioned? There is the case where a monk, quite withdrawn from sensuality, withdrawn from unskillful (mental) qualities, enters & remains in the first jhana: rapture & pleasure born from withdrawal, accompanied by directed thought & evaluation. His consciousness follows the drift of the rapture & pleasure born of withdrawal, is tied to... chained... fettered, & joined to the attraction of the rapture & pleasure born of withdrawal. Or further, with the stilling of directed thoughts & evaluations, he enters & remains in the second jhana: rapture & pleasure born of concentration, unification of awareness free from directed thought & evaluation — internal assurance. His consciousness follows the drift of the rapture & pleasure born of composure, is tied to... chained... fettered, & joined to the attraction of the rapture & pleasure born of composure. Or further, with the fading of rapture, he remains equanimous, mindful, & alert, and senses pleasure with the body. He enters & remains in the third jhana, of which the Noble Ones declare, 'Equanimous & mindful, he has a pleasant abiding.' His consciousness follows the drift of the equanimity & pleasure, is tied to... chained... fettered, & joined to the attraction of the equanimity & pleasure. Or further, with the abandoning of pleasure & pain — as with the earlier disappearance of elation & distress — he enters & remains in the fourth jhana: purity of equanimity & mindfulness, neither pleasure nor pain. His consciousness follows the drift of the neither pleasure nor pain, is tied to... chained to... fettered, & joined to the attraction of the neither pleasure nor pain: The mind is said to be internally positioned.
"And how is the mind said not to be internally positioned? There is the case where a monk, quite withdrawn from sensuality, withdrawn from unskillful (mental) qualities, enters & remains in the first jhana: rapture & pleasure born from withdrawal, accompanied by directed thought & evaluation. His consciousness does not follow the drift of the rapture & pleasure born of withdrawal, is not tied to... chained to... fettered, or joined to the attraction of the rapture & pleasure born of withdrawal. Or further, with the stilling of directed thoughts & evaluations, he enters & remains in the second jhana: rapture & pleasure born of concentration, unification of awareness free from directed thought & evaluation — internal assurance. His consciousness does not follow the drift of the rapture & pleasure born of composure, is not tied to... chained... fettered, or joined to the attraction of the rapture & pleasure born of composure. Or further, with the fading of rapture, he remains equanimous, mindful, & alert, and senses pleasure with the body. He enters & remains in the third jhana, of which the Noble Ones declare, 'Equanimous & mindful, he has a pleasant abiding.' His consciousness does not follow the drift of the equanimity & pleasure, is not tied to... chained... fettered, or joined to the attraction of the equanimity & pleasure. Or further, with the abandoning of pleasure & pain — as with the earlier disappearance of elation & distress — he enters & remains in the fourth jhana: purity of equanimity & mindfulness, neither pleasure nor pain. His consciousness does not follow the drift of the neither pleasure nor pain, is not tied to... chained to... fettered, or joined to the attraction of the neither pleasure nor pain: The mind is said to be not internally positioned.
"And how is agitation caused by clinging/sustenance? There is the case where an uninstructed, run-of-the-mill person — who has no regard for noble ones, is not well-versed or disciplined in their Dhamma; who has no regard for men of integrity, is not well-versed or disciplined in their Dhamma — assumes form to be the self, or the self as possessing form, or form as in the self, or the self as in form. His form changes & is unstable. Because of the change & instability of form, his consciousness alters in accordance with the change in form. With the agitations born from the alteration in accordance with the change in form and coming from the co-arising of (unskillful mental) qualities, his mind stays consumed. And because of the consumption of awareness, he feels fearful, threatened, & solicitous.
"He assumes feeling to be the self...
"He assumes perception to be the self...
"He assumes (mental) fabrications to be the self...
"He assumes consciousness to be the self, of the self as possessing consciousness, or consciousness as in the self, or the self as in consciousness. His consciousness changes & is unstable. Because of the change & instability of consciousness, his consciousness alters in accordance with the change in consciousness. With the agitations born from the alteration in accordance with the change in consciousness and coming from the co-arising of (unskillful mental) qualities, his mind stays consumed. And because of the consumption of awareness, he feels fearful, threatened, & solicitous.
"This, friends, is how agitation is caused by clinging/sustenance.
"And how is non-agitation caused by lack of clinging/ sustenance? There is the case where an instructed disciple of the noble ones — who has regard for nobles ones, is well-versed & disciplined in their Dhamma; who has regard for men of integrity, is well-versed & disciplined in their Dhamma — doesn't assume form to be the self, or the self as possessing form, or form as in the self, or the self as in form. His form changes & is unstable, but his consciousness doesn't — because of the change & instability of form — alter in accordance with the change in form. His mind is not consumed with any agitations born from an alteration in accordance with the change in form or coming from the co-arising of (unskillful mental) qualities. And because his awareness is not consumed, he feels neither fearful, threatened, nor solicitous.
"He doesn't assume feeling to be the self...
"He doesn't assume perception to be the self...
"He doesn't assume fabrications to be the self...
"He doesn't assume consciousness to be the self, or the self as possessing consciousness, or consciousness as in the self, or the self as in consciousness. His consciousness changes & is unstable, but his consciousness doesn't — because of the change & instability of consciousness — alter in accordance with the change in consciousness. His mind is not consumed with any agitations born from an alteration in accordance with the change in consciousness or coming from the co-arising of (unskillful mental) qualities. And because his awareness is not consumed, he feels neither fearful, threatened, nor solicitous.
"This, friends, is how non-agitation is caused by lack of clinging/sustenance.
"So, concerning the brief statement the Blessed One made, after which he entered his dwelling without analyzing the detailed meaning — i.e., 'A monk should investigate in such a way that, his consciousness neither externally scattered & diffused, nor internally positioned, he would from lack of clinging/sustenance be unagitated. When — his consciousness neither externally scattered & diffused, nor internally positioned — from lack of clinging/ sustenance he would be unagitated, there is no seed for the conditions of future birth, aging, death, or stress' — this is how I understand the detailed meaning. Now, if you wish, having gone to the Blessed One, question him about this matter. However he answers is how you should remember it."
Then the monks, delighting in & approving of Ven. Maha Kaccayana's words, rose from their seats and went to the Blessed One. On arrival, having bowed down to him, they sat to one side. As they were sitting there, they [told him what had happened after he had gone into his dwelling, and ended by saying,] "Then Ven. Maha Kaccayana analyzed the meaning using these words, these statements, these phrases."
"Maha Kaccayana is wise, monks. He is a person of great discernment. If you had asked me about this matter, I too would have answered in the same way he did. That is the meaning of this statement. That is how you should remember it."
That is what the Blessed One said. Gratified, the monks delighted in the Blessed One's words.