32. Those who split up their religion, and become (mere) Sects,- Each party rejoicing In that which is with itself!
33. When trouble touches men, They cry to their Lord, turning back to Him In repentance: but when He gives them a taste of Mercy As from Himself, Behold, some of them pay part-worship to other god's besides their Lord,-
Koran Ar-Rum 31-33.
This verses explain that make sect or parties is forbidden by Allah in Islam. This action of make sects or parties is weakening Islam from inside. where each party said that it the best sect, so would be there is no best exist.