Islam advocates peace and peace-making. However, fighting and war is permitted in certain circumstances when all else has been tried and failed.
"O mankind! We created you from a single (pair) of a male and a female, and made you into nations and tribes, that ye may know each other (not that ye may despise each other)." - Surah 49:13
"O mankind! We created you from a single (pair) of a male and a female, and made you into nations and tribes, that ye may know each other (not that ye may despise each other)." - Surah 49:13