An-Nisa' - 4:65

فَلاَ وَرَبِّكَ لاَ يُؤْمِنُونَ حَتَّىَ يُحَكِّمُوكَ فِيمَا شَجَرَ بَيْنَهُمْ ثُمَّ لاَ يَجِدُواْ فِي أَنفُسِهِمْ حَرَجًا مِّمَّا قَضَيْتَ وَيُسَلِّمُواْ تَسْلِيمًا
[4:65]
But no! by your Lord! they do not believe (in reality) until they make you a judge of that which has become a matter of disagreement among them, and then do not find any straitness in their hearts as to what you have decided and submit with entire submission.
But no, by the Lord, they can have no (real) Faith, until they make thee judge in all disputes between them, and find in their souls no resistance against Thy decisions, but accept them with the fullest conviction.
But nay, by thy Lord, they will not believe (in truth) until they make thee judge of what is in dispute between them and find within themselves no dislike of that which thou decidest, and submit with full submission.