"[Shall I seek other than Allah as judge, while it is He who has sent down to you the Book, explained in detail?]" meaning: clarified, as He has made clear therein guidance and misguidance, and the lawful and the unlawful.
"[And those to whom We gave the Scripture know that it is sent down from your Lord in truth]" meaning: the learned among the People of the Scripture. "[So never be among the doubters]" meaning: those who doubt that this Quran is from Allah, and [know] that the learned among the People of the Scripture know that it is sent down from your Lord in truth.
﴿أَفَغَيْرَ اللَّهِ أَبْتَغِي حَكَمًا وَهُوَ الَّذِي أَنْزَلَ إِلَيْكُمُ الْكِتَابَ مُفَصَّلا﴾ أَيْ: مُبَيَّنًا، بَيَّنَ فِيهِ الْهُدَى وَالضَّلَالَةَ، وَالْحَلَالَ وَالْحَرَامَ.
﴿وَالَّذِينَ آتَيْنَاهُمُ الْكِتَابَ يَعْلَمُونَ أَنَّهُ مُنَزَّلٌ مِنْ رَبك بِالْحَقِّ﴾ يَعْنِي: أَهْلَ الدِّرَاسَةِ مِنْ أَهْلِ الْكِتَابِ ﴿فَلا تَكُونَنَّ مِنَ الْمُمْتَرِينَ﴾ يَعْنِي: الشَّاكِّينَ أَنَّ هَذَا الْقُرْآنَ مِنْ عِنْدَ اللَّهِ، وَأَنَّ أَهْلَ الدِّرَاسَةِ مِنْ أَهْلِ الْكِتَابِ يَعْلَمُونَ أَنَّهُ مُنَزَّلٌ مِنْ رَبِّكَ بِالْحَقِّ.
