Niccolo Machiavelli - Discourses on the First Decade of Titus Livius (Chap. 2.28) lyrics

That to neglect the redress of Grievances, whether public or private, is dangerous for a Prince or Commonwealth. Certain Gauls coming to attack Etruria, and more particularly Clusium its chief city, the citizens of Clusium sought aid from Rome; whereupon the Romans sent the three Fabii, as envoys to these Gauls, to notify to them, in the name of the Roman people, that they must refrain from making war on the Etruscans. From what befell the Romans in connection with this emba**y, we see clearly how far men may be carried in resenting an affront. For these envoys arriving at the very moment when the Gauls and Etruscans were about to join battle, being readier at deeds than words, took part with the Etruscans and fought in their foremost ranks. Whence it came that the Gauls recognizing the Roman envoys, turned against the Romans all the hatred which before they had felt for the Etruscans; and grew still more incensed when on making complaint to the Roman senate, through their amba**ador, of the wrong done them, and demanding that the Fabii should be given up to them in atonement for their offence, not merely were the offenders not given up or punished in any way, but, on the contrary, when the comitia met were created tribunes with consular powers. But when the Gauls found these men honoured who deserved to be chastised, they concluded that what had happened had been done by way of slight and insult to them, and, burning with fury and resentment, hastened forward to attack Rome, which they took with the exception of the Capitol. Now this disaster overtook the Romans entirely from their disregard of justice. For their envoys, who had violated the law of nations, and had therefore deserved punishment, they had on the contrary treated with honour. And this should make us reflect, how carefully all princes and commonwealths ought to refrain from committing like wrongs, not only against communities, but also against particular men. For if a man be deeply wronged, either by a private hand or by a public officer, and be not avenged to his satisfaction, if he live in a republic, he will seek to avenge himself, though in doing so he bring ruin on his country; or if he live under a prince, and be of a resolute and haughty spirit, he will never rest until he has wreaked his resentment against the prince, though he knows it may cost him dear. Whereof we have no finer or truer example than in the d**h of Philip of Macedon, the father of Alexander. For Pausanias, a handsome and high-born youth belonging to Philip's court, having been most foully and cruelly dishonoured by Attalus, one of the foremost men of the royal household, repeatedly complained to Philip of the outrage; who for a while put him off with promises of vengeance, but in the end, so far from avenging him, promoted Attalus to be governor of the province of Greece. Whereupon, Pausanias, seeing his enemy honoured and not punished, turned all his resentment from him who had outraged, against him who had not avenged him, and on the morning of the day fixed for the marriage of Philip's daughter to Alexander of Epirus, while Philip walked between the two Alexanders, his son and his son-in-law, towards the temple to celebrate the nuptials, he slew him. This instance nearly resembles that of the Roman envoys; and offers a warning to all rulers never to think so lightly of any man as to suppose, that when wrong upon wrong has been done him, he will not bethink himself of revenge, however great the danger he runs, or the punishment he thereby brings upon himself.