It is of course not enough for a nation to possess strength, its leader must be ready, willing, and able to exercise it at a moment’s notice. That exercise is war. We make war to achieve peace. Peace is the end of war in a two-fold sense: war’s cessation and war’s goal. We do not make war for the sake of war, but for the sake of peace.
But there is another view of war, the agonal view of Ernst Jünger (1895-1998). The following from Heinrich Meier, The Lesson of Carl Schmitt (University of Chicago Press, expanded ed., 2011, pp. 39-40, bolding added):
The opposition between agonal and political thought bears upon the meaning of war and the destiny of man. On the one hand, war is considered the expression of eternal coming to be and passing away and, since it is arising from the nature of man, is affirmed as such. On the other hand, it is regarded as a state that does not have its raison d’etre within but rather beyond itself. From this standpoint war is not the lord or king that allots each the share he is due as the result of free contest and the measuring of one’s strengths against others, but rather the slave in the service of a higher order. Over against the agonal principle, according to which man is not designed for peace, stands the political principle according to which man cannot achieve his destiny save by committing himself wholly and existentially to the realization of dominion, order, and peace. [Carl] Schmitt can speak of a “great metaphysical opposition” because he sees in agonal thought man’s attempt to give meaning, that is, to join in the cosmic play, and sould the greatest succeed, to fight a good fight, whereas he believes he sees the the most profound basis of political thought in the dependence of everything on whether one takes up the fight for the sake of the good and withstands it as a divine trial.