The Jataka, Vol. II, tr. by W.H.D. Rouse, , at sacred-texts.com
 "Rough to the rough," etc.--This story the Master told whilst he was living in Jetavana, to explain how a king was taught a lesson.
This will be set forth in the Tesakuṇa Birth 2.
It is said that one day the king of Kosala had just passed sentence in a very difficult case involving moral wrong 3. After his meal, with hands not yet dry, he proceeded in his splendid chariot to visit the Master; and the king saluted him, his feet beautiful like the open lotus flower, and sat down aside.
Then the Master addressed him in these words. "Why, my lord king, what brings you here at this time of day?" "Sir," said he, "I missed my time because I was sitting on a difficult case, involving moral wrong; now I have finished it, and eaten, and here I am, with my hands hardly dry, to wait upon you." "My lord king," replied the Master, "to judge a cause with justice and impartiality is the right thing; that is the way to heaven. Now when you first have the advice of a being all-wise like me, it is no wonder if you should judge your case fairly and justly; but the wonder is when kings have only had the advice of scholars who are not all-wise, and yet have decided fairly and justly, avoiding the Four Ways of Wickedness, and observing the Ten Royal Virtues, and after ruling justly have gone to swell the hosts of heaven." Then, at the king's request, he told a story of the olden time.
 Once upon a time, when Brahmadatta was king of Benares, the Bodhisatta was conceived by his Queen Consort; and the ceremonies proper to her state having been duly done 4, she was afterwards safely
delivered. On his name-day, the name they gave him was Prince Brahmadatta.
In course of time, he grew up, and at sixteen years went to Takkasilā 1 for his education; where he mastered all branches of learning, and on his father's death he became king in his stead, and ruled with uprightness and all rectitude, administering justice with no regard had to his own will or whim. And as he ruled thus justly, his ministers on their part were also just; thus, while all things were justly done, there was none who brought a false suit into court. Presently all the bustle of suitors ceased within the precincts of the palace; all day long the ministers might sit on the bench, and go away without seeing a single suitor. The courts were deserted.
Then the Bodhisatta thought to himself, "Because of my just government not one suitor comes to try issue in court; the old hubbub is quiet; the courts of law are deserted. Now I must search whether I have any fault in me; which if I find, I will eschew it, and live a good life hereafter." From that time he tried continually to find some one who would tell him of a fault; but of all who were about him at court he could not find one such; nothing could he hear but good of himself. "Perhaps," thought he, "they are all so much afraid of me that they say no ill of me but only good," and so he went about to try those who were outside his walls. But with these it was just the same. Then he made inquisition of the citizens at large, and outside the city questioned those who belonged to the suburbs at the four city gates. Still there was none who had any fault to find; nothing but praises could he hear. Lastly, with intent to try the country side, he entrusted all government to his ministers, and mounted in his carriage, and taking only the driver with him, left the city in disguise. All the country he traversed, even to the frontier;  but not a faultfinder could he light upon; all he could hear was only his own praises. So back he turned from the marches, and set his face homewards again by the highroad.
Now it fortuned that at this very time Mallika, the king of Kosala, had done the very same thing. He too was a just king, and he had been searching for his faults; but amongst those about him there was none who had any fault to find; and hearing nothing but praise, he had been making enquiry throughout all the country, and had but then arrived at that same spot.
These two met, in a place where the .carriage-road was deeply sunk between two banks, and there was no room for one carriage to pass another.
Get your carriage out of the way!" said king Mallika's driver to the driver of the king of Benares.
"No, no, driver," said he, "out of the way with yours! Know that in this carriage sits the great monarch Brahmadatta, lord of the kingdom of Benares!"
"Not so, driver!" replied the other, "in this carriage sits the great king Mallika, lord of the realm of Kosala! It is for you to make way, and to give place to the carriage of our king!"
"Why, here's a king too," thought the driver of the king of Benares. "What in the world is to be done?" Then a thought struck him; he would enquire what should be the age of the two kings, so that the younger should give way to the elder. And he made enquiry of the other driver how old his king was; but he learnt that both were of the same age. Thereupon he asked the extent of this king's power, wealth, and glory, and all points touching his caste and clan and his family; discovering that both of them had a country three hundred leagues long, and that they were alike in power, wealth, glory, and the nature of their family and lineage. Then he bethought him that place might be given to the better man; so he requested that the other driver should describe his master's virtues. The man replied by the first verse of poetry following, in which he set forth his monarch's faults as though they were so many virtues:--
 "Oh," said the man of the king of Benares, "is that all you have to say about your king's virtues?" "Yes," said the other.--"If these are his virtues, what must his vices be?" "Vices be it, then," quoth he, "if you will; but let us hear what your king's virtues may be like!" "Listen then," rejoined the first, and repeated the second verse:--
At these words both king Mallika and his driver descended from their carriage, and loosed the horses, and moved it out of the way, to give place to the king of Benares. Then the king of Benares gave good admonition to king Mallika, saying, "Thus and thus  must you do;" after which he returned to Benares, and there gave alms and did good all his life, till at the last the went to swell the hosts of heaven. And king Mallika took the lesson to heart; and after traversing the length and breadth of the
land, and lighting upon none who had any fault to find, returned to his own city; where he gave alms all his life and did good, till at the end he too went to swell the hosts of heaven.
When the Master had ended this discourse, which he began for the purpose of giving a lesson to the king of Kosala, he identified the Birth: "Moggallāna was then the driver of king Mallika, Ānanda was the king, Sāriputta was the driver of the king of Benares, but I myself was the king."
1:1 Fausbøll, Ten J., pp. 1 and 57; Rhys Davids, Buddhist Birth Stories, p. xxii. A similar contest of two minstrels occurs in the Kalevala (Crawford's translation, i. p. 30). The young drives fiercely into the old, who says--'Thou shouldst give me all the highway, for I am the older.' 'What matters that?' says the other; 'let the least wise give place.' There they stand and each sings his legends by way of deciding the matter.
1:2 No. 521.
1:3 Reading, with Childers (Diet. p. 613), agatigataṁ.
1:4 Lit. "protection to the embryo;" doubtless some magical rite.
2:1 The great University town of India; it was in the Punjab (Τάξιλα).
3:1 Dhammapada, verse 223.