Carl von Clausewitz

If defense is the stronger form of war, yet has a negative object, it follows that it should be used only so long as weakness compels, and be abandoned as soon as we are strong enough to pursue a positive object.

...in war, the advantages and disadvantages of a single action could only be determined by the final balance.

What is the object of defense? To preserve. To preserve is easier than to acquire.

The more physical the activity, the less the difficulties will be. The more the activity becomes intellectual and turns into motives which exercise a determining influence on the commander's will, the more the difficulties will increase.

Of all the passions that inspire a man in a battle, none, we have to admit, is so powerful and so constant as the longing for honor and renown.

A conqueror is always a lover of peace (as Bonaparte always asserted of himself); he would like to make his entry into our state unopposed; in order to prevent this, we must choose war, and therefore also make preparations, that is in other words, it is just the weak, or that side which must defend itself, which should be always armed in order not to be taken by surprise; so it is willed by the art of war. (Original German: "Der Eroberer ist immer friedliebend (wie Bonaparte auch stets behauptet hat), er zöge ganz gern ruhig in unseren Staat ein; damit er dies aber nicht könne, darum müssen wir den Krieg wollen und also auch vorbereiten, d. h. mit anderen Worten: es sollen gerade die Schwachen, der Verteidigung Unterworfenen, immer gerüstet sein und nicht überfallen werden; so will es die Kriegskunst.")

Any complex activity, if it is to be carried on with any degree of virtuosity, calls for appropriate gifts of intellect and temperament. If they are outstanding and reveal themselves in exceptional achievements, their possessor is called a 'genius'.

Our discussion has shown that while in war many different roads can lead to the goal, to the attainment of the political object, fighting is the only possible means.

Everything in war is simple, but the simplest thing is difficult.

Boldness will be at a disadvantage only in an encounter with deliberate caution, which may be considered bold in its own right, and is certainly just as powerful and effective; but such cases are rare.

All war presupposes human weakness and seeks to exploit it.

Knowledge must be so absorbed into the mind that it ceases to exist in a separate, objective way.