There will always be vexation and grief.

Aye! by thy Lord, they shall not believe until they have made thee judge of that which is disputed among them, and then find no vexation in their hearts with that which thou hast decreed, and they submit with full submission.

But no, by your Lord, they cannot become true be lievers until they seek your arbitration in all matters on which they disagree among themselves, and then find not the least vexation in their hearts over what you have decided, and accept it in willing submission.