At one point, the king of Magadha led his army to attack and occupy Kashi, then invaded Kosala. The king of Kosala, unprepared for battle, suffered a defeat at the hands of the Magadhan army. He retreated to his capital city of Shravasti.

In Shravasti, King Kosala urgently convened a military council with his ministers to find ways to counter the continued invasion by the Magadhan army. Following advice from his ministers and strategists, he dispatched messengers to various countries allied with Kosala requesting reinforcements. He also sent strategies for rescuing Kosala along with requests for help to some kings who had close relationships with him.

Soon after that, eight kings promised to send troops to help King Kosala repel the Magadhan army. Four of these kingdoms took advantage of the fact that most of Magadha's forces were outside their country and occupied large areas in Magadha while surrounding its capital city. The other four kingdoms launched surprise attacks on and burned much of the food supplies belonging to the invading force.

The situation suddenly became dire for King Ajatasattu's army as morale plummeted among soldiers who fought each other over food while deserters increased in number. Taking advantage of this opportunity, King Kosala launched a surprise attack on Ajatasattu's camp outside Shravasti at night during which he captured Ajatasattu himself alive.

The next day when victory was secured by King Kosala, he addressed generals, ministers and people saying: "I have not done anything wrong against my nephew (Ajatasattu). However this young man has no respect for heaven or earth; he dared invade my territory after occupying Kashi! This is an act against all righteousness! Even his father did not dare do such things! Who gave him such courage? I will take all his elephant troops, cavalry troops, chariot troops and infantry under my command. Out of respect for his father and because he is my nephew, I will spare his life but he cannot escape punishment. He will be exiled to a border city where he can experience the pain of being homeless." 

At that time, there were many monks who would put on their robes before noon and carry their alms bowls to the city to beg for food. After eating, they would go to the Buddha's residence and pay respects. One elder said to the Buddha, "World Honored One, today while we were begging in the city, we heard that King Ajatashatru's army had been defeated by King Bimbisara's army. King Bimbisara captured King Ajatashatru and announced his intention of taking all of Ajatashatru's soldiers under his own command. He also plans to exile him far away so he can experience what it is like to be homeless."

The Buddha already knew about this matter and told the monks seeking guidance: "People in this world rob and plunder others' possessions, land, and people for their own benefit. When others are robbed or plundered they will try to take back what originally belonged to them. Those who rob and plunder others will also be robbed and plundered by others.

Ignorant people think that what they have obtained through robbery or theft belongs solely to themselves; they do not believe in cause-and-effect karma nor do they believe that robbing or stealing from others will result in being robbed or stolen from themselves. They don't believe that causing trouble or pain for others will bring similar troubles upon themselves; instead thinking these consequences are false illusions.

They even consider robbing other people’s property as a natural thing but actually planting seeds of hatred within themselves which eventually lead them into suffering when those seeds grow into bitter fruits.

Killing or harming someone else is killing or harming oneself; those who kill or harm others will also be killed/harmed by someone else.

Defeating another person means defeating oneself while allowing another person victory; those who defeat another person causing them distress/pain will also be defeated by someone else bringing distress/pain to themselves.

Mocking, ridiculing, insulting or slandering others is mocking, ridiculing, insulting or slandering oneself. Those who mock, ridicule, insult or slander others will also be mocked, ridiculed, insulted or slandered by someone else.

Creating trouble and obstacles for others causing them distress/pain is creating trouble and obstacles for oneself causing distress/pain. Those who create trouble and obstacles for others causing them distress/pain will also have the same done to themselves.

This is the cycle of karmic retribution; this is the cycle of cause-and-effect karma. No one in this world can escape from it nor avoid its consequences. Those who rob and plunder from others will also be robbed and plundered."

At this time, the Buddha spoke a verse:

"When one seeks only personal gain,

By taking from others what they have,

Those who were robbed will rob in turn,

For fools think this is right and just.

But when their evil ways bear fruit,

They suffer pain and great distress.

If one should kill another person,

The killer too will meet his end.

And if one triumphs over others,

He'll be defeated in his turn.

When mocking or despising others

One brings about oneself disgrace;

And he who harms another's life

Will soon endure an equal fate.

Thus does the wheel of karma turn:

What goes around comes back again."

King Pasenadi was informed of the Buddha's teachings to his renounced disciples. He immediately changed his mind and released King Ajatasattu, returning all the captured elephants, horses, chariots, prisoners, gold and jewels to him. He also provided a large amount of food for King Ajatasattu's army. To express his gratitude towards the eight countries that helped him defeat King Ajatasattu's army, he gave them abundant treasures. Furthermore, he persuaded the countries that had occupied a large part of Magadha territory and besieged its capital city to retreat upon hearing that he had released King Ajatasattu and returned all his military equipment including soldiers, elephants and horses.

After paying homage to the Buddha at his residence, King Ajatasattu expressed his gratitude for saving his life by offering all the wealth brought with him before leaving for war as offerings to the Buddha. He promised not to provoke any more wars against Kosala in future. Reluctantly bidding farewell to the Buddha afterwards, King Ajatasattu led his army back home.

Pali original scripture

SN.3.15/(5). Dutiyasaṅgāmasuttaṃ

　　 126. Atha kho rājā māgadho ajātasattu vedehiputto caturaṅginiṃ senaṃ sannayhitvā rājānaṃ pasenadiṃ kosalaṃ abbhuyyāsi yena kāsi. Assosi kho rājā pasenadi kosalo– “rājā kira māgadho ajātasattu vedehiputto caturaṅginiṃ senaṃ sannayhitvā mamaṃ abbhuyyāto yena kāsī”ti. Atha kho rājā pasenadi kosalo caturaṅginiṃ senaṃ sannayhitvā rājānaṃ māgadhaṃ ajātasattuṃ vedehiputtaṃ paccuyyāsi yena kāsi. Atha kho rājā ca māgadho ajātasattu vedehiputto rājā ca pasenadi kosalo saṅgāmesuṃ. Tasmiṃ kho pana saṅgāme rājā pasenadi kosalo rājānaṃ māgadhaṃ ajātasattuṃ vedehiputtaṃ parājesi, jīvaggāhañca naṃ aggahesi. Atha kho rañño pasenadissa kosalassa etadahosi– “kiñcāpi kho myāyaṃ rājā māgadho ajātasattu vedehiputto adubbhantassa dubbhati, atha ca pana me bhāgineyyo hoti. Yaṃnūnāhaṃ rañño māgadhassa ajātasattuno vedehiputtassa sabbaṃ hatthikāyaṃ pariyādiyitvā sabbaṃ assakāyaṃ pariyādiyitvā sabbaṃ rathakāyaṃ pariyādiyitvā sabbaṃ pattikāyaṃ pariyādiyitvā jīvantameva naṃ osajjeyyan”ti.

　　 Atha kho rājā pasenadi kosalo rañño māgadhassa ajātasattuno vedehiputtassa sabbaṃ hatthikāyaṃ pariyādiyitvā sabbaṃ assakāyaṃ pariyādiyitvā sabbaṃ rathakāyaṃ pariyādiyitvā sabbaṃ pattikāyaṃ pariyādiyitvā jīvantameva naṃ osajji.

　　 Atha kho sambahulā bhikkhū pubbaṇhasamayaṃ nivāsetvā pattacīvaramādāya sāvatthiṃ piṇḍāya pavisiṃsu. Sāvatthiyaṃ piṇḍāya caritvā pacchābhattaṃ piṇḍapātapaṭikkantā yena bhagavā tenupasaṅkamiṃsu; upasaṅkamitvā bhagavantaṃ abhivādetvā ekamantaṃ nisīdiṃsu. Ekamantaṃ nisinnā kho te bhikkhū bhagavantaṃ etadavocuṃ–

　　 “Idha bhante, rājā māgadho ajātasattu vedehiputto caturaṅginiṃ senaṃ sannayhitvā rājānaṃ pasenadiṃ kosalaṃ abbhuyyāsi yena kāsi. Assosi kho, bhante, rājā pasenadi kosalo– ‘rājā kira māgadho ajātasattu vedehiputto caturaṅginiṃ senaṃ sannayhitvā mamaṃ abbhuyyāto yena kāsī’ti. Atha kho, bhante, rājā pasenadi kosalo caturaṅginiṃ senaṃ sannayhitvā rājānaṃ māgadhaṃ ajātasattuṃ vedehiputtaṃ paccuyyāsi yena kāsi. Atha kho, bhante, rājā ca māgadho ajātasattu vedehiputto rājā ca pasenadi kosalo saṅgāmesuṃ. Tasmiṃ kho pana, bhante, saṅgāme rājā pasenadi kosalo rājānaṃ māgadhaṃ ajātasattuṃ vedehiputtaṃ parājesi, jīvaggāhañca naṃ aggahesi. Atha kho, bhante, rañño pasenadissa kosalassa etadahosi– ‘kiñcāpi kho myāyaṃ rājā māgadho ajātasattu vedehiputto adubbhantassa dubbhati, atha ca pana me bhāgineyyo hoti. Yaṃnūnāhaṃ rañño māgadhassa ajātasattuno vedehiputtassa sabbaṃ hatthikāyaṃ pariyādiyitvā sabbaṃ assakāyaṃ sabbaṃ rathakāyaṃ sabbaṃ pattikāyaṃ pariyādiyitvā jīvantameva naṃ osajjeyyan’”ti.

　　 “Atha kho, bhante, rājā pasenadi kosalo rañño māgadhassa ajātasattuno vedehiputtassa sabbaṃ hatthikāyaṃ pariyādiyitvā sabbaṃ assakāyaṃ pariyādiyitvā sabbaṃ rathakāyaṃ pariyādiyitvā sabbaṃ pattikāyaṃ pariyādiyitvā jīvantameva naṃ osajjī”ti. Atha kho bhagavā etamatthaṃ viditvā tāyaṃ velāyaṃ imā gāthāyo abhāsi–

　　 “Vilumpateva puriso, yāvassa upakappati;

　　 Yadā caññe vilumpanti, so vilutto viluppati.

　　 “Ṭhānañhi maññati bālo, yāva pāpaṃ na paccati;

　　 Yadā ca paccati pāpaṃ, atha dukkhaṃ nigacchati.

　　 “Hantā labhati hantāraṃ, jetāraṃ labhate jayaṃ;

　　 Akkosako ca akkosaṃ, rosetārañca rosako.

　　 Atha kammavivaṭṭena, so vilutto viluppatī”ti.