M. Tullius Cicero Pro A. Cluentio 128

[128]
  For that indeed can never be allowed, that they should transfer the usage of military discipline to the animadversions and authority of the censors; for our ancestors established a rule, that if in military affairs a crime had been committed by a number of soldiers, a few should be punished by lot, that so fear might have its influence on all, while the punishment reached only a few. But how can it be fitting for the censors to act on this principle in the distribution of dignities, in their judgment on the character of citizens, and in their punishment of their vices? For a soldier who has not maintained his post, who has been afraid of the vigorous attack of the enemy, may still hereafter become a better soldier, and a virtuous man, and a useful citizen. Wherefore, to prevent his committing offences in time of war through fear of the enemy, the great fear of death and execution was established by our ancestors; but yet, that the number of those who underwent capital punishment might not be too great, that plan of drawing lots was invented.