The Jataka, Volume I, tr. by Robert Chalmers, , at sacred-texts.com
"If poison lurk."--This story was told about the Licchavi Prince Wicked of Vesālī by the Master when he was living in the gabled house in the great forest near Vesālī. In those days Vesālī enjoyed marvellous prosperity. A triple wall encompassed the city, each wall a league distant from the next, and there were three gates with watch-towers. In that city there were always seven thousand seven hundred and seven kings to govern the kingdom, and a like number of viceroys, generals, and treasurers. Among the kings' sons was one known as Wicked Licchavi Prince, a fierce, passionate and cruel young man, always punishing, like an enraged viper. Such was his passionate nature that no one could say more than two or three words in his presence; and neither parents, kindred, nor friends could make him better. So at last his parents resolved to bring the ungovernable youth to the All-Wise Buddha, realising that none but he could possibly tame their son's fierce spirit. So they brought him to the Master, whom, with due obeisance, they besought to read the youth a lecture.
Then the Master addressed the prince and said: "Prince, human beings should not be passionate or cruel or ferocious. The fierce man is one who is harsh and unkind alike to the mother that bore him, to his father and child, to his brothers and sisters, and to his wife, friends and kindred; inspiring terror like a viper darting forward to bite, like a robber springing on his victim in the forest, like an ogre advancing to devour, the fierce man straightway will be re-born after this life in hell or other place of punishment; and even in this life,
however much adorned he is, he looks ugly. Be his face beautiful as the orb of the moon at the full, yet is it loathly as a lotus scorched by flames, as a disc of gold overworn with filth. It is such rage that drives men to slay themselves with the sword, to take poison, to hang themselves, and to throw themselves from precipices; and so it comes to pass that, meeting their death by reason of their own rage, they are re-born into torment. So too they who injure others, are hated even in this life and shall for their sins pass at the body's death to hell and punishment; and when once more they are born as men,  disease and sickness of eye and ear and of every kind ever beset them, from their birth onward. Wherefore let all men shew kindness and be doers of good, and then assuredly hell and punishment have no fears for then."
Such was the power of this one lecture upon the prince that his pride was humbled forthwith; his arrogance and selfishness passed from him, and his heart was turned to kindness and love. Nevermore did he revile or strike, but became gentle as a snake with drawn fangs, as a crab with broken claws, as a bull with broken horns.
Marking this change of mood, the Brethren talked together in the Hall of Truth of how the Licchavi Prince Wicked, whom the ceaseless exhortations of his parents could not curb, had been subdued and humbled with a single exhortation by the All-Wise Buddha, and how this was like taming six rutting elephants at once. Well had it been said that, 'The elephant-tamer, Brethren, guides the elephant he is breaking in, making it to go to right or left, backward or forward, according to his will; in like manner the horse-tamer and the ex-tamer with horses and oxen; and so too the Blessed One, the All-wise Buddha, guides the man he would train aright, guides him whithersoever he wills along any of the eight directions, and makes his pupil discern shapes external to himself. Such is the Buddha and He alone,'--and so forth, down to the words,--'He that is hailed as chief of the trainers of men, supreme in bowing men to the yoke of Truth 1.' "For, sirs," said the Brethren, "there is no trainer of men like unto the Supreme Buddha."
And here the Master entered the Hall and questioned them as to what they were discussing. Then they told him, and he said, "Brethren, this is not the first time that a single exhortation of mine has conquered the prince; the like happened before."
And so saying, he told this story of the past.
Once on a time when Brahmadatta was reigning in Benares, the Bodhisatta came to life again as a brahmin in the North country, and when he grew up he first learned the Three Vedas and all learning, at Takkasilā, and for some time lived a mundane life. But when his parents died he became a recluse, dwelling in the Himalayas, and attained the mystic Attainments and Knowledges. There he dwelt a long time, till need of salt and other necessaries of life brought him back to the paths of men, and he came to Benares, where he took up his quarters in the royal pleasaunce. Next day he dressed himself with care and pains, and in the best garb of an ascetic went in quest of alms to the city  and came to the king's gate. The king was sitting down and saw the Bodhisatta from the window and marked within himself how the hermit, wise in heart and soul, fixing his gaze immediately before him, moved on in lion-like majesty, as though at every
footstep he were depositing a purse of a thousand pieces. "If goodness dwell anywhere," thought the king, "it must be in this man's breast." So summoning a courtier, he bade him bring the hermit into the presence. And the courtier went up to the Bodhisatta and with due obeisance, took his alms-bowl from his hand. "How now, your excellency?" said the Bodhisatta. "The king sends for your reverence," replied the courtier. "My dwelling," said the Bodhisatta, "is in the Himalayas, and I have not the king's favour."
So the courtier went back and reported this to the king. Bethinking him that he had no confidential adviser at the time, the king bade the Bodhisatta be brought, and the Bodhisatta consented to come.
The king greeted him on his entrance with great courtesy and bade him be seated on a golden throne beneath a royal parasol. And the Bodhisatta was fed on dainty food which had ḅeen made ready for the king's own eating.
Then the king asked where the ascetic lived and learned that his home was in the Himalayas.
"And where are you going now?"
"In search, sire, of a habitation for the rainy season."
"Why not take up your abode in my pleasaunce?" suggested the king. Then, having gained the Bodhisatta's consent, and having eaten food himself, he went with his guest to the pleasaunce and there had a hermitage built with a cell for the day, and a cell for the night. This dwelling was provided with the eight requisites of an ascetic. Having thus installed the Bodhisatta, the king put him under the charge of the gardener and went back to the palace. So it came to pass that the Bodhisatta dwelt thenceforward in the king's pleasaunce, and twice or thrice every day the king came to visit him.
Now the king had a fierce and passionate son who was known as Prince Wicked, who was beyond the control of his father and kinsfolk. Councillors, brahmins and citizens all pointed out to the young man the error of his ways, but in vain. He paid no heed to their counsels. And the king felt that the only hope of reclaiming his son lay with the virtuous ascetic. So as a last chance  he took the prince and handed him over to the Bodhisatta to deal with. Then the Bodhisatta walked with the prince in the pleasaunce till they came to where a seedling Nimb tree was growing, on which as yet grew but two leaves, one on one side, one on the other.
"Taste a leaf of this little tree, prince," said the Bodhisatta, "and see what it is like."
The young man did so; but scarce had he put the leaf in his mouth, when he spat it out with an oath, and hawked and spat to get the taste out of his mouth,
"What is the matter, prince?" asked the Bodhisatta.
"Sir, to-day this tree only suggests a deadly poison; but, if left to grow, it will prove the death of many persons," said the prince, and forthwith plucked up and crushed in his hands the tiny growth, reciting these lines:--
Then said the Bodhisatta to him, "Prince, dreading what the poisonous seedling might grow to, you have torn it up and rent it asunder. Even as you acted to the tree, so the people of this kingdom, dreading what a prince so fierce and passionate may become when king, will not place you on the throne but uproot you like this Nimb tree and drive you forth to exile. Wherefore take warning by the tree and henceforth shew mercy and abound in loving-kindness."
From that hour the prince's mood was changed. He grew humble and meek, merciful and overflowing with kindness. Abiding by the Bodhisatta's counsel,  when at his father's death he came to be king, he abounded in charity and other good works, and in the end passed away to fare according to his deserts.
His lesson ended, the Master said, "So, Brethren, this is not the first time that I have tamed Prince Wicked; I did the same in days gone by." Then he identified the Birth by saying, "The Licchavi Prince Wicked of to-day was the Prince Wicked of the story, Ānanda the king, and I the ascetic who exhorted the prince to goodness."
317:1 The quotation has not been traced in published texts.