Knowledge in war is very simple, being concerned with so few subjects, and only with their final results at that. But this does not make its applicat… - Carl von Clausewitz

Surprise becomes effective when we suddenly face the enemy at one point with far more troops than he expected. This type of numerical superiority is quite distinct from numerical superiority in general: it is the most powerful medium in the art of war.

Der Soldat wird ausgehoben, gekleidet, bewaffnet, geübt, er schläft, ißt, trinkt und marschiert, alles nur, um an rechter Stelle und zu rechter Zeit zu fechten.

...as man under pressure tends to give in to physical and intellectual weakness, only great strength of will can lead to the objective.