Allāh Decreed the Division of the Ummah
In the Name of Allāh, the Ever Merciful, the Bestower of Mercy
Without a doubt, this division causes pain to every Muslim. It is mandatory upon the Muslims to gather upon the truth and to work together upon goodness and piety; however, Allāh decreed the division of the Ummah due to His great wisdom and praiseworthy objectives, for which He should be praised. No one knows its details except Him. Differentiating His awliyā’ [i.e friends] from His enemies and differentiating those who exert themselves to seek the truth from those who turn away from it, following their desires, are from those objectives.
Source: al-Ajwibah al-Athariyyah, pg. 184-185.
Translated by: Musa Shaleem Mohammed