Division of Islam (Firqa-parasti)

1)  As for those who divide their religion and break up into sects, thou hast no part in them in the least: their affair is with Allah: He will in the end tell them the truth of all that they did. (Surah 6, Al-An’am, Verse 159).

2) ....It was after knowledge had been granted to them, that they fell into schisms. Verily Allah will judge between them as to the Schisms amongst them, on the Day of Judgment. (Surah 10, Yunus, Verse 93 Part).

3) Verily, this brotherhood of yours is a single Brotherhood, and I am your Lord and

Cherisher: therefore serve Me (and no other). But (later generations) cut off their affair (of

unity), one from another: (yet) will they all return to Us. (Surah 21, Al-Anbiyya, verses 92-93).

4) But people have cut off their affair (of unity), between them, into sects: each party rejoices in that which is with itself. But leave them in their confused ignorance for a time (Surah 23, Al-Mu’minun, verses 53-54).

5) Turn ye back in repentance to Him, and fear Him: establish regular prayers, and be not ye among those who join gods with Allah, - Those who split up their Religion, and become (mere) Sects, - each party rejoicing in that which is with itself! (Surah 30. Ar-Rum, verses 31-32).

6) The same religion has He established for you as that which He enjoined on Noah - the which We have sent by inspiration to thee - and that which We enjoined on Abraham, Moses, and Jesus: Namely, that ye should remain steadfast in religion, and make no divisions therein: to those who worship other things than Allah, hard is the (way) to which thou callest them.  Allah chooses to Himself those whom He pleases, and guides to Himself those who turn (to Him). And they became divided only after Knowledge reached them, - through selfish envy as between themselves. Had it not been for a Word that went forth before from thy Lord, (tending) to a Term appointed, the matter would have been settled between them: But truly those who have inherited the Book after them are in suspicious (disquieting) doubt concerning it. (Surah 42, Al-Shura, verses 13-14).

7) The Religion before Allah is Islam (submission to His Will): Nor did the People of the Book dissent therefrom except through envy of each other, after knowledge had come to them. But if any deny the Signs of Allah, Allah is swift in calling to account (Surah 3, Al-Imran, verse 19).

8) Do they seek for other than the Religion of Allah.- while all creatures in the heavens and on earth have, willing or unwilling, bowed to His Will (Accepted Islam), and to Him shall they all be brought back.(Surah 3, Al-Imran, verse 83).

9) Nor did the People of the Book make schisms, until after there came to them Clear Evidence. (Surah 98, Al-Bayyinah, verse 4).

10) Narrated Ibn Mas'ud: I heard a person reciting a (Quranic) Verse in a certain way, and I had heard the Prophet (Peace be upon him) reciting the same verse in a different way. So I took him to the Prophet (Peace be upon him) and informed him of that but I noticed the sign of disapproval on his face, and then he said, "Both of you are correct, so don't differ, for the nations before you differed, so they were destroyed." (Sahih Bukhari: Volume 4, Book 56, Number 682: Book of The Merits of Sunnah) (Islambase Publications).