Quran 6:114 from Surah Al-An'aam on Divine Marvels.
أَفَغَيۡرَ ٱللَّهِ أَبۡتَغِي حَكَمٗا وَهُوَ ٱلَّذِيٓ أَنزَلَ إِلَيۡكُمُ ٱلۡكِتَٰبَ مُفَصَّلٗاۚ وَٱلَّذِينَ ءَاتَيۡنَٰهُمُ ٱلۡكِتَٰبَ يَعۡلَمُونَ أَنَّهُۥ مُنَزَّلٞ مِّن رَّبِّكَ بِٱلۡحَقِّۖ فَلَا تَكُونَنَّ مِنَ ٱلۡمُمۡتَرِينَ
English translation: Then is (it) other than Allah I seek (as) judge while He (is) the One Who has revealed to you the Book explained in detail And those (to) whom We gave them the Book they know that it (is) sent down from your Lord in truth so (do) not be among the ones who doubt
Transliteration: afaghayra al-lahi abtaghi hakaman wahuwa alladhi anzala ilaykumu al-kitaba mufassalan wa-alladhina ataynahumu al-kitaba ya'lamuna annahu munazzalun min rabbika bil-haqi fala takunanna mina al-mum'tarina