أَفَغَيْرَ ٱللَّهِ أَبْتَغِى حَكَمًا وَهُوَ ٱلَّذِىٓ أَنزَلَ إِلَيْكُمُ ٱلْكِتَٰبَ مُفَصَّلًا وَٱلَّذِينَ ءَاتَيْنَٰهُمُ ٱلْكِتَٰبَ يَعْلَمُونَ أَنَّهُۥ مُنَزَّلٌ مِّن رَّبِّكَ بِٱلْحَقِّ فَلَا تَكُونَنَّ مِنَ ٱلْمُمْتَرِينَ ١١٤
[Say], "Then is it other than Allāh I should seek as judge while it is He who has revealed to you the Book [i.e., the Qur’ān] explained in detail?" And those to whom We [previously] gave the Scripture know that it is sent down from your Lord in truth, so never be among the doubters.
Explanation: Al-Mukhtasar
Say, O Messenger, to these idolaters who worship others together with Allah: Does it make sense for me to accept anyone other than Allah as a judge between us whilst Allah is the One Who has revealed the Qur’ān which sufficiently explains everything. The Jews, to whom I gave the Torah, and the Christians, to whom I gave the Gospel, know that the Qur’ān has been revealed to you, because the proof of that is found in their scriptures. So do not be of those who doubt about what I revealed to you.