​MN 128 Upakkilesa Sutta: Imperfections 

​Thus have i heard.

On one occasion the Blessed One was living at Kosambi in Ghosita's Park. Now on that occasion the bhikkhus at Kosambi had taken to quarreling and brawling and were deep in disputes, stabbing each other with verbal daggers. Then a certain bhikkhu went to report the matter to the Blessed One: "Venerable sir, the bhikkhus here at Kosambi have taken to quarreling and verbally abusing each other. It would be good, venerable sir, if the Blessed One would go to those bhikkhus out of compassion." The Blessed One consented in silence.

Then the Blessed One went to those bhikkhus and said to them: "Enough, bhikkhus, let there be no quarreling or dispute." When this was said, a certain bhikkhu said to the Blessed One: "Wait, venerable sir! Let the Blessed One, the Lord of the Dhamma, live at ease devoted to a pleasant abiding here and now. We are the ones who will be responsible for this quarreling, brawling, wrangling, and dispute." For a second time...For a third time the Blessed One said: "Enough, bhikkhus, let there be no quarreling or dispute." For a third time that bhikkhu said to the Blessed One: "Wait, venerable sir!...We are the ones who will be responsible for this quarreling, brawling, wrangling, and dispute."

Then the next morning, the Blessed One dressed, and taking his bowl and outer robe, entered Kosambi for alms. When he had wandered for alms in Kosambi and had returned from his alms round, after his meal he set his resting place in order, took his bowl and outer robe, and while still standing uttered these stanzas:

​ "When many voices shout at once, None considers himself a fool;
Though the Sangha is being split, None thinks himself to be at fault. 

They have forgotten thoughtful speech, They talk obsessed by words alone.
Uncurbed their mouths, they bawl at will; None knows what leads him so to act. 

'He abused me, he struck me, He defeated me, he robbed me'
In those who harbor thoughts like these Hatred will never be allayed. 

For in this world hatred is never Allayed by further acts of hate.
It is allayed by non-hatred: That is the fixed and ageless law. 

Those others do not recognize That here we should restrain ourselves.
But those wise ones who realize this At once end all their enmity. 

Breakers of bones and murderers, Those who steal cattle, horses, wealth,
Those who pillage the entire realm When even these can act together Why can you not do so too? 
​
If one can find a worthy friend, A virtuous, steadfast companion,
Then overcome all threats of danger And walk with him content and mindful. 

But if one finds no worthy friend, No virtuous, steadfast companion,
Then as a king leaves his conquered realm, Walk like a tusker in the woods alone. 

​​Better it is to walk alone, There is no companionship with fools.
Walk alone and do no evil, At ease like a tusker in the woods."
Then, having uttered these stanzas while standing, the Blessed One went to the village of Balakalonakara. On that occasion, the venerable Bhagu was living at the village of Balakalonakara. When the venerable Bhagu saw the Blessed One coming in the distance, he prepared a seat and set out water for washing the feet. The venerable Bhagu paid homage to the Blessed One and sat down at one side, and the Blessed One said to him: "I hope you are keeping well, bhikkhu, I hope you are comfortable, I hope you are not having any trouble getting alms food."

Bhagu: "I am keeping well, Blessed One, I am comfortable, and I am not having any trouble getting alms food." Then the Blessed One instructed, urged, roused, and encouraged the venerable Bhagu with talk on the Dhamma, after which he rose from his seat and went to the Eastern Bamboo Park.

Now on that occasion the venerable Anuruddha, the venerable Nandiya and the venerable Kimbila were living at the Eastern Bamboo Park. The park keeper saw the Blessed One coming in the distance and told him: "Do not enter this park, recluse. There are three clansmen here seeking their own good. Do not disturb them." The venerable Anuruddha heard the park keeper speaking to the Blessed One and told him: "Friend park keeper, do not keep the Blessed One out. It is our Teacher, the Blessed One, who has come."

Then the venerable Anuruddha went to the venerable Nandiya and the venerable Kimbila and said: "Come out, venerable sirs, come out! Our Teacher, the Blessed One, has come."  Then all three went to meet the Blessed One. One took his bowl and outer robe, one prepared a seat, and one set out water for washing the feet. Then those three venerable ones paid homage to the Blessed One and sat down at one side, and the Blessed One said to them: "I hope you are all keeping well, Anuruddha, I hope you are comfortable, I hope you are not having any trouble getting almsfood."
They replied: "We are keeping well, Blessed One, we are comfortable, and we are not having any trouble getting almsfood." 
Buddha: "I hope, Anuruddha, that you are all living in concord, with mutual appreciation, without disputing, blending like milk and water, viewing each other with kindly eyes."
Anuruddha: "Surely, venerable sir, we are living in concord, with mutual appreciation, without disputing, blending like milk and water, viewing each other with kindly eyes."
Buddha: "But, Anuruddha, how do you live thus?"
Anuruddha: "Venerable sir, as to that, I think thus: 'It is a gain for me, it is a great gain for me that I am living with such companions in the holy life.' I maintain bodily acts of loving-kindness towards these venerable ones both openly and privately; I maintain verbal acts of loving-kindness towards them both openly and privately; I maintain mental acts of loving-kindness towards them both openly and privately. I consider: 'Why should I not set aside what I wish to do and do what these venerable ones wish to do?' Then I set aside what I wish to do and do what these venerable ones wish to do. We are different in body, venerable sir, but one in mind."

The venerable Nandiya and the venerable Kimbila each spoke likewise, adding: "That is how, venerable sir, we are living in concord, with mutual appreciation, without disputing, blending like milk and water, viewing each other with kindly eyes."
Buddha: "Good, good, Anuruddha. I hope that you all abide diligent, ardent, and resolute."
Anuruddha: "Surely, venerable sir, we abide diligent, ardent, and resolute."

Buddha: "But, Anuruddha, how do you abide thus?"
Anuruddha: "Venerable sir, as to that, whichever of us returns first from the village with alms food prepares the seats, sets out the water for drinking and for washing, and puts the refuse bucket in its place. Whichever of us returns last eats any food left over, if he wishes; otherwise he throws it away where there is no greenery or drops it into water where there is no life. He puts away the seats and the water for drinking and for washing. He puts away the refuse bucket after washing it, and he sweeps out the refectory. Whoever notices that the pots of water for drinking, washing, or the latrine are low or empty takes care of them. If they are too heavy for him, he calls someone else by a signal of the hand and they move it by joining hands, but because of this we do not break out into speech. But every five days we sit together all night discussing the Dhamma. That is how we abide diligent, ardent, and resolute." 
​Buddha: "Good, good, Anuruddha. But while you abide thus diligent, ardent, and resolute, have you attained any superhuman states, a distinction in knowledge and vision worthy of the noble ones, a comfortable abiding?" Anuruddha: "Venerable sir, as we abide here diligent, ardent, and resolute, we perceive both light and a vision of forms. Soon afterwards the light and the vision of forms disappear, but we have not discovered the cause for that."

Buddha: "You should discover the cause for that,Anuruddha. Before my enlightenment, while I was still only an unenlightened Bodhisatta, I too perceived both light and a vision of forms. Soon afterwards the light and the vision of forms disappeared. I thought: 'What is the cause and condition why the light and the vision of forms have disappeared?' Then I considered thus: 'Doubt arose in me, and because of the doubt my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared. I shall so act that doubt will not arise in me again.' "

"As, Anuruddha, I was abiding diligent, ardent, and resolute, I perceived both light and a vision of forms. Soon afterward the light and the vision of forms disappeared. I thought: 'What is the cause and condition why the light and the vision of forms have disappeared?' Then I considered thus: 'Inattention arose in me, and because of inattention my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared. I shall so act that neither doubt nor inattention will arise in me again.' "

"As, Anuruddha, I was abiding diligent...I considered thus: 'Sloth and torpor arose in me, and because of sloth and torpor my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared. I shall so act that neither doubt nor inattention nor sloth and torpor will arise in me again.' As, Anuruddha, I was abiding diligent...! considered thus: 'Fear arose in me, and because of fear my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared.' Suppose a man set out on a journey and murderers leaped out on both sides of him; then fear would arise in him because of that. So too, fear arose in me.. .the light and the vision of forms disappeared. I considered thus: 'I shall so act that neither doubt nor inattention nor sloth and torpor nor fear will arise in me again.'"

​"As, Anuruddha, I was abiding diligent...I considered thus: 'Elation arose in me, and because of elation my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared.' Suppose a man seeking one entrance to a hidden treasure came all at once upon five entrances to a hidden treasure; then elation would arise in him because of that. So too, elation arose in me...the light and the vision of forms disappeared. I considered thus: 'I shall so act that neither doubt nor inattention...nor fear nor elation will arise in me again.'"

"As, Anuruddha, I was abiding diligent...I considered thus: 'Inertia arose in me, and because of inertia my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared. I shall so act that neither doubt nor inattention.. .nor elation nor inertia will arise in me again.' As, Anuruddha, I was abiding diligent...I considered thus: 'Excess of energy arose in me, and because of excess of energy my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared.' Suppose a man were to grip a quail tightly with both hands; it would die then and there. So too, an excess of energy arose in me...the light and the vision of forms disappeared. I considered thus: 'I shall so act that neither doubt nor inattention...nor inertia nor excess of energy will arise in me again.'"

"As, Anuruddha, I was abiding diligent...I considered thus: 'Deficiency of energy arose in me, and because of deficiency of energy my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared.' Suppose a man were to grip a quail loosely; it would fly out of his hands. So too, a deficiency of energy arose in me.. .the light and the vision of forms disappeared. I considered thus:'I shall so act that neither doubt nor inattention...nor excess of energy nor deficiency of energy will arise in me again.' "
​"As, Anuruddha, I was abiding diligent...I considered thus: 'Longing arose in me, and because of that longing my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared. I shall so act that neither doubt nor inattention.. .nor deficiency of energy nor longing will arise in me again.'  As, Anuruddha, I was abiding diligent...I considered thus: 'Perception of diversity arose in me, and because of perception of diversity my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared. I shall so act that neither doubt nor inattention...nor longing nor perception of diversity will arise in me again.' "

"As, Anuruddha, I was abiding diligent...I considered thus: 'Excessive meditation upon forms arose in me, and because of excessive meditation upon forms my concentration fell away; when my concentration fell away, the light and the vision of forms disappeared. I shall so act that neither doubt nor inattention...nor perception of diversity nor excessive meditation upon forms will arise in me again.' "

When, Anuruddha, I understood that doubt is an imperfection of the mind,I abandoned doubt, an imperfection of the mind. When I understood that inattention...sloth and torpor... fear... elation... inertia... excess of energy...deficiency of energy...longing...perception of diversity...excessive meditation upon forms is an imperfection of the mind, I abandoned excessive meditation upon forms, an imperfection of the mind. "

"As, Anuruddha, I was abiding diligent, ardent, and resolute, I perceived light but I did not see forms; I saw forms but I did not perceive light, even for a whole night or a whole day or a whole day and night. I thought: 'What is the cause and condition for this?' Then I considered thus: 'On the occasion when I do not attend to the sign of forms but attend to the sign of light, I then perceive light but do not see forms. On the occasion when I do not attend to the sign of light but attend to the sign of forms, I then see forms but do not perceive light, even for a whole night or a whole day or a whole day and night.' "

"As, Anuruddha, I was abiding diligent, ardent, and resolute, I perceived limited light and saw limited forms; I perceived immeasurable light and saw immeasurable forms, even for a whole night or a whole day or a whole day and night. I thought: 'What is the cause and condition for this?' Then I considered thus: 'On the occasion when concentration is limited, my vision is limited, and with limited vision I perceive limited light and limited forms. But on the occasion when concentration is immeasurable, my vision is immeasurable, and with immeasurable vision I perceive immeasurable light and see immeasurable forms, even for a whole night or a whole day or a whole day and night.' "
"When Anuruddha, I understood that doubt is an imperfection of the mind and had abandoned doubt, an imperfection of the mind; when I understood that inattention is an imperfection of the mind and had abandoned inattention... abandoned sloth and torpor...abandoned fear...abandoned elation... abandoned inertia...abandoned excess of energy...abandoned deficiency of energy...abandoned longing...abandoned perception of diversity...abandoned excessive meditation upon forms, an imperfection of the mind; then I thought: 'I have abandoned those imperfections of the mind. Let me now develop Concentration in three ways.'"

"Thereupon, Anuruddha, I developed concentration with applied thought and sustained thought; I developed concentration without applied thought but with sustained thought only; I developed concentration without applied thought and without sustained thought; I developed concentration with rapture; I developed concentration without rapture; I developed concentration accompanied by enjoyment; I developed concentration accompanied by equanimity. When, Anuruddha, I had developed concentration with applied thought and sustained thought...when I had developed concentration accompanied by equanimity, the knowledge and vision arose in me: 'My deliverance is unshakeable; this is my last birth; now there is no renewal of being.'"

That is what the Blessed One said. The venerable Anuruddha was satisfied and delighted in the Blessed One's words. 
​In summary, the Buddha is not able to halt the argument of the sangha in Ghosita's vihara in Kosambī and so he moves on to visit Bhagu in Balakallonakara village where he teaches him Dhamma and then he visits Venerable Anuruddha and other monks staying in the Eastern Bamboo Grove there. Buddha asked Venerable Anuruddha how the monks can live in harmony, they replied through bodily, mentally and verbally acts of loving kindness. This is different from the group of sangha members who could not live in peace earlier in Ghosita. When the bhikkhus do not live in harmony with each other they obstruct their access to Dhamma, when they live in harmony access to Dhamma appears.

The buddha teaches the Venerable Anuruddh in great detail the process of eliminating the five hindrances during  meditation which he encountered before his enlightenment. Then he describes the method of jhana practice in threes which he himself used to attain arahantship. 
References: 
1. www.accesstoinsight.org
2. https://suttacentral.net/
3. The Middle discourses of the Buddha (Bhikkhu Bodhi)