Richard Landsberg

“But the Byzantines knew that there was no end, that new enemies would emerge if the old were utterly defeated, and there was an even chance that they might be as dangerous or more dangerous. In that case, the enemy fleet left undestroyed might be useful, for the newcomers might be as threatening to the old enemy as to the empire. It was the same on land, where to destroy one enemy pressing against the imperial frontiers would merely leave a vacant space for the next enemy to threaten imperial borders. Therefore the purpose of war for the Byzantines could not be to seek battle for decisive victory, for there was no such thing, but only to contain immediate threats by weakening the enemy with expedients, ruses of war, and ambushes, leaving any form of two-sided large-scale combat as only a last resort. That is the strategic context of this, as of every piece of serious Byzantine military writing.”
― Edward N. Luttwak, The Grand Strategy of the Byzantine Empire