I have heard:
On one occasion the Blessed One was staying among the Calikans, at Calika Mountain. At that time Ven. Meghiya was his attendant. Then Ven. Meghiya went to the Blessed One and, on arrival, having bowed down to him, stood to one side. As he was standing there he said to the Blessed One, "I would like to go into Jantu Village for alms."
"Then do, Meghiya, what you think it is now time to do."
Then in the early morning, Ven. Meghiya, having put on his robes and carrying his bowl and outer robe, went into Jantu Village for alms. Having gone for alms in Jantu Village, after the meal, returning from his alms round, he went to the banks of the Kimikala River. As he was walking along the banks of the river to exercise his legs, he saw a pleasing, charming mango grove. Seeing it, the thought occurred to him: "How pleasing and charming is this mango grove! It's an ideal place for a young man of good family intent on exertion to exert himself in meditation. If the Blessed One gives me permission, I would like to exert myself in meditation in this mango grove."
So Ven. Meghiya went to the Blessed One and, on arrival, having bowed down to him, sat to one side. As he was sitting there he said to the Blessed One, "Just now, in the early morning, having put on my robes and carrying my bowl and outer robe, I went into Jantu Village for alms. Having gone for alms in Jantu Village, after the meal, returning from my alms round, I went to the banks of the Kimikala River. As I was walking along the banks of the river to exercise my legs, I saw a pleasing, charming mango grove. Seeing it, the thought occurred to me: 'How pleasing and charming is this mango grove! It's an ideal place for a young man of good family intent on exertion to exert himself in meditation. If the Blessed One gives me permission, I would like to exert myself in meditation in this mango grove.' If the Blessed One gives me permission, I would like to go to the mango grove to exert myself in meditation."
When this was said, the Blessed One responded to Ven. Meghiya, "As long as I am still alone, stay here until another monk comes."
A second time, Ven. Meghiya said to the Blessed One, "Lord, the Blessed One has nothing further to do, and nothing further to add to what he has done. I, however, have something further to do, and something further to add to what I have done. If the Blessed One gives me permission, I would like to go to the mango grove to exert myself in meditation."
A second time, the Blessed One responded to Ven. Meghiya, "As long as I am still alone, stay here until another monk comes."
A third time, Ven. Meghiya said to the Blessed One, "Lord, the Blessed One has nothing further to do, and nothing further to add to what he has done. I, however, have something further to do, and something further to add to what I have done. If the Blessed One gives me permission, I would like to go to the mango grove to exert myself in meditation."
"As you are talking about exertion, Meghiya, what can I say? Do what you think it is now time to do."
Then Ven. Meghiya, rising from his seat, bowing down to the Blessed One and circling him to the right, went to the mango grove. On arrival, having gone deep into the grove, he sat down at the foot of a certain tree for the day's abiding.
Now while Ven. Meghiya was staying in the mango grove, he was for the most part assailed by three kinds of unskillful thoughts: sensual thoughts, thoughts of ill will, and thoughts of doing harm. The thought occurred to him: "How amazing! How awesome! Even though it was through faith that I went forth from home to the homeless life, still I am overpowered by these three kinds of unskillful thoughts: sensual thoughts, thoughts of ill will, and thoughts of doing harm." Emerging from his seclusion in the late afternoon, he went to the Blessed One and, on arrival, having bowed down to him, sat to one side. As he was sitting there he said to the Blessed One, "Just now, while I was staying in the mango grove, I was for the most part assailed by three kinds of unskillful thoughts: sensual thoughts, thoughts of ill will, and thoughts of doing harm. The thought occurred to me: 'How amazing! How awesome! Even though it was through faith that I went forth from home to the homeless life, still I am overpowered by these three kinds of unskillful thoughts: sensual thoughts, thoughts of ill will, and thoughts of doing harm.'"
"Meghiya, in one whose release of awareness is still immature, five qualities bring it to maturity. Which five?
"There is the case where a monk has admirable people as friends, companions, and colleagues. In one whose release of awareness is still immature, this is the first quality that brings it to maturity.
"Furthermore, the monk is virtuous. He dwells restrained in accordance with the Patimokkha, consummate in his behavior and sphere of activity. He trains himself, having undertaken the training rules, seeing danger in the slightest faults. In one whose release of awareness is still immature, this is the second quality that brings it to maturity.
"Furthermore, he gets to hear at will, easily and without difficulty, talk that is truly sobering and conducive to the opening of awareness, i.e., talk on having few wants, on contentment, on seclusion, on non-entanglement, on arousing persistence, on virtue, on concentration, on discernment, on release, and on the knowledge and vision of release. In one whose release of awareness is still immature, this is the third quality that brings it to maturity.
"Furthermore, he keeps his persistence aroused for abandoning unskillful [mental] qualities and for taking on skillful qualities. He is steadfast, solid in his effort, not shirking his duties with regard to skillful qualities. In one whose release of awareness is still immature, this is the fourth quality that brings it to maturity.
"Furthermore, he is discerning, endowed with the discernment of arising and passing away -- noble, penetrating, leading to the right ending of stress. In one whose release of awareness is still immature, this is the fifth quality that brings it to maturity.
"Meghiya, when a monk has admirable people as friends, companions, and colleagues, it is to be expected that he will be virtuous, will dwell restrained in accordance with the Patimokkha, consummate in his behavior and sphere of activity, and will train himself, having undertaken the training rules, seeing danger in the slightest faults.
"When a monk has admirable people as friends, companions, and colleagues, it is to be expected that he will get to hear at will, easily and without difficulty, talk that is truly sobering and conducive to the opening of awareness, i.e., talk on having few wants, on contentment, on seclusion, on non-entanglement, on arousing persistence, on virtue, on concentration, on discernment, on release, and on the knowledge and vision of release.
"When a monk has admirable people as friends, companions, and colleagues, it is to be expected that he will keep his persistence aroused for abandoning unskillful qualities, and for taking on skillful qualities -- steadfast, solid in his effort, not shirking his duties with regard to skillful qualities.
"When a monk has admirable people as friends, companions, and colleagues, it is to be expected that he will be discerning, endowed with discernment of arising and passing away -- noble, penetrating, leading to the right ending of stress.
"And furthermore, when the monk is established in these five qualities, there are four additional qualities he should develop: He should develop [contemplation of] the unattractive so as to abandon lust. He should develop good will so as to abandon ill will. He should develop mindfulness of in-and-out breathing so as to cut off distractive thinking. He should develop the perception of inconstancy so as to uproot the conceit, 'I am.' For a monk perceiving inconstancy, the perception of not-self is made firm. One perceiving not-self attains the uprooting of the conceit, 'I am' -- Unbinding in the here and now."
Then, on realizing the significance of that, the Blessed One on that occasion exclaimed:
Little thoughts, subtle thoughts,
when followed, stir up the heart.
Not comprehending the thoughts of the heart,
one runs here & there,
the mind out of control.
But comprehending the thoughts of the heart,
one who is ardent, mindful,
restrains them.
When, followed, they stir up the heart,
one who is awakened
lets them go without trace.