War is the manifestation of two opposites.
I define war as the manifestation of two opposites. If you move you encounter opposition of air resistance and gravity, this opposition is war. You might comment that there is difference between a bomb blowing up people and you facing the wind as you walk to work; they are the same because there are oppositions in play.
Heraclitus considers that the patterns that repeat over time are “common” and it is worth basing our ideas, attitudes and behaviors on what is common than the children’s toys of blind opinion. In nature war is common, and in human society war is also common.
All things in nature are good, only humanity breaks nature into subjective judgements of good and bad. Fire is neither good nor bad, but it is common and will either provide you with warmth on a cold day, or burn you to death in a house fire. War is common, being the manifestation of opposites your heart muscles work in opposition to each other so that you might live, but an opposition of a bullet to the heart would kill you.
Harmony is the result of those that work with the common in nature. When you face the opposition of winter you put on warm clothes, when you face the opposition of summer, you put on less clothes. The difference between human species and other living things in nature is that we choose to hold opinions and follow strategies in direct opposition to the common patterns of nature. There is no harmony for the fool who goes naked in a winter snow storm.
To work with war in order to achieve harmony, the first action is to drop blind subjective opinions that war is good or bad. War is as common as fire and should be treated as a force in nature like fire and breathing. All living things excluding humanity treat war as common and work with the oppositions of war along the path of least resistance towards a harmony.
Humanity is the fool for creating needless war. If I believed and acted upon the idea I could get all I wanted by stealing it, I would create a great deal of war from those I stole from. If I trade for anything I needed then there would be less war. In situations of war the wise employ strategies that work with the oppositions, I was a fool when camping in a storm, and nearly died under a falling tree.
In closing I shall comment briefly on the example of the recent fighting between Israel and Palestine. One of the complex reasons for this oppositions resulting in war is the unity of opposites where each side seeks to deny the existence of the other, so that an existential crisis arises where a side is forced to fight or end in oblivion. When two sides share the same existential space where neither can withdraw to another space, the strategy is either going to be total genocide of one side or be doomed to failure, thus the path of least resistance must be something other than bombs and bullets to achieve a harmony between two opposing sides. If two sides of the heart can find a harmony in the opposites thus creating life to the whole, so there is a hidden answer in the current opposition between Israel and Palestine, but only the wise will see it.