
“Good officers never engage in general actions unless induced by opportunity or obliged by necessity.”
Boni duces publico certamine numquam nisi ex occasione aut nimia necessitate confligunt.
De Re Militari (also Epitoma Rei Militaris), Book III, "Dispositions for Action"
Context: Punishment, and fear thereof, are necessary to keep soldiers in order in quarters; but in the field they are more influenced by hope and rewards. Good officers never engage in general actions unless induced by opportunity or obliged by necessity. (General Maxims)