Say, "He is the [one] Able to send upon you affliction from above you or from beneath your feet or to confuse you [so you become] sects and make you taste the violence of one another." Look how We diversify the signs that they might understand. (Surah Al Anam :Verse 65)
Indeed, those who have divided their religion and become sects - you, [O Muhammad], are not [associated] with them in anything. Their affair is only [left] to Allah ; then He will inform them about what they used to do (Surah Al Anam : Verse 159)
Very importance verses in today's times when we are getting divided amongst ourselves on basis of various schools of thought! Think about it.