Luxury is the origin of war.
-Plato (The Republic)

War is the result of greed and the desire to have more than what is necessary. Or to feed an appetite that requires excessive materials. For example oil. Oil is used to create many items, some of which are necessary, many of which are not. Since the wealthy countries that use the most oil cannot sustain their use of oil war is necessary to take over countries that have oil. Other examples can be used such as gold, or diamonds and other luxuries.

If it was not for the desire to amass more possessions than the rest of the world there would be no need for war. It's too bad to think that the reason so many people die so unjustly is merely for a countries greed.

Without the presence of luxury all people could be satisfied with the resources available.