If soldiers are punished before they have grown attached to you, they will not prove submissive; and, unless submissive, then will be practically useless. If, when the soldiers have become attached to you, punishments are not enforced, they will still be unless.
As one reads history, not in the expurgated editions written for schoolboys and passmen, but in the original authorities of each time, one is absolutely sickened, not by the crimes that the wicked have committed, but by the punishments that the good have inflicted; and a community is infinitely more brutalised by the habitual employment of punishment than it is by the occasional occurrence of crime.
The infernal storm, eternal in its rage, sweeps and drives the spirits with its blast; it whirls them, lashing them with punishment. When they are swept back past their place of judgment then come the shrieks, laments, and anguished cries; there they blaspheme God's almighty power.
This game is repeated again and again, and in it the role of the so-called 'German princes' is just as miserable as that of the Jews themselves. These lords were really God's punishment for their beloved peoples and find their parallels only in the various ministers of the present time.
But secondly you say 'society must exact vengeance, and society must punish'. Wrong on both counts. Vengeance comes from the individual and punishment from God.