Qur'an does teach peace and harmony. In encouraging people to seek peace and maintain it, the Qur'an states that the purpose behind the creation of different tribes and various nations is to interact and know each other and not to be a reason to fight each other. The Qur'an states in Surah 49, verse 13, the meaning of:
*{O mankind! We created you from a single pair of a male and a female, and made you into nations and tribes, that you may know each other.}*
To emphasize the importance of peace and harmony among people, the message of Islam, from the beginning, declared the unity of mankind in its three aspects; origin, value and destiny.
Peaceful Harmony? or Violent Intolerance? - WorldView - counsels - OnIslam.net
Crap! the quran is a book that promotes separation, and tribalism, and war.
The quran says the curse of God is on unbelievers in Allah and the day of judgement and they will burn in eternal hellfire. Here are some verses on fighting.
2.216 Fighting is prescribed for you, and ye dislike it. But it is possible that ye dislike a thing which is good for you, and that ye love a thing which is bad for you. But God knoweth, and ye know not.
4.74 Let those fight in the cause of God Who sell the life of this world for the hereafter. To him who fighteth in the cause of God,- whether he is slain or gets victory - Soon shall We give him a reward of great (value).
4.76 Those who believe fight in the cause of God, and those who reject Faith Fight in the cause of Evil: So fight ye against the friends of Satan: feeble indeed is the cunning of Satan.
9.29 Fight those who believe not in God nor the Last Day, nor hold that
forbidden which hath been forbidden by God and His Apostle, nor acknowledge the religion of Truth, (even if they are) of the People of the Book, until they pay the Jizya with willing submission, and feel themselves subdued.
9.123 O ye who believe! fight the unbelievers who gird you about, and let them find firmness in you: and know that God is with those who fear Him.
48.16 Say to the desert Arabs who lagged behind: "Ye shall be summoned (to fight) against a people given to vehement war: then shall ye fight, or they shall submit. Then if ye show obedience, God will grant you a goodly reward, but if ye turn back as ye did before, He will punish you with a grievous Penalty."