Is it necessary to rage a war against other countries  

Yep, that's quite natural. But my question here is not directing to the other countries like poland, france and other countries who were invaded and then dragged into war. My question is for the leaders of countries who are over ambitious and try to acquire more land and they do this at the cost of other peoples lives, mainly the common man. For a common man, his motto is to earn a livelihood and stay peacefully with his family. But due to these leaders, the common man is also emotionally provoked which leads to Satan's ultimate goal, create fight between humans.