From whence come wars and fightings among you? come they not hence, even of your lusts that war in your members? Ye lust, and have not: ye kill, and desire to have, and cannot obtain: ye fight and war, yet ye have not, because ye ask not. Ye ask, and receive not, because ye ask amiss, that ye may consume it upon your lusts. Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God. Do ye think that the scripture saith in vain, The spirit that dwelleth in us lusteth to envy? But he giveth more grace. Wherefore he saith, God resisteth the proud, but giveth grace unto the humble.
Many ask why God allows war if He is such a good God. Well, He gives us free will and war occurs because of selfish desires. We desire more than what we have so we fight and kill. Even if we do ask God for something, we won't receive it if we ask out of selfishness. We can not desire things of the world and things of God at the same time. If we want "success" in the eyes of the world, then we will be against the Lord.
However, if we humble ourselves before God, He will show us grace. We must make a choice-our pride or God.