Qur’an Karim Sura 21
 
إِنَّ هَـٰذِهِ أُمَّتُكُمْ أُمَّةً وَاحِدَةً وَأَنَا رَبُّكُمْ فَاعْبُدُونِ ﴿٩٢﴾
(92) Verily, this brotherhood of yours is a single brotherhood, and I am your Lord and Cherisher: therefore serve Me (and no other).
وَتَقَطَّعُوا أَمْرَهُم بَيْنَهُمْ ۖ كُلٌّ إِلَيْنَا رَاجِعُونَ ﴿٩٣﴾
(93) But (later generations) cut off their affair (of unity), one from another: (yet) will they all return to Us.