3:66
هَٰٓأَنتُمْ هَٰٓؤُلَآءِ حَٰجَجْتُمْ فِيمَا لَكُم بِهِۦ عِلْمٌۭ فَلِمَ تُحَآجُّونَ فِيمَا لَيْسَ لَكُم بِهِۦ عِلْمٌۭ ۚ وَٱللَّهُ يَعْلَمُ وَأَنتُمْ لَا تَعْلَمُونَ
Here you are - those who have argued about that of which you have [some] knowledge, but why do you argue about that of which you have no knowledge? And Allah knows, while you know not.
Translation · Saheeh International
Tafsir
Ibn Kathīr (abridged)
Disputing with the Jews and Christians About the Religion of Ibrahim
Allah censures the Jews and Christians for their dispute with Muslims over Ibrahim Al-Khalil and the claim each group made that he was one of them. Muhammad bin Ishaq bin Yasar reported that Ibn `Abbas said, "The Christians of Najran and Jewish rabbis gathered before the Messenger of Allah ﷺ and disputed in front of him. The rabbis said, `Ibrahim was certainly Jewish.' The Christians said, `Certainly, Ibrahim was Christian.' So Allah sent down,
يأَهْلَ الْكِتَـبِ لِمَ تُحَآجُّونَ فِى إِبْرَهِيمَ
(O people of the Scripture (Jews and Christians)! Why do you dispute about Ibrahim,) meaning, `How is it that you, Jews, claim that Ibrahim was Jew, although he lived before Allah sent down the Tawrah to Musa How is it that you, Christians, claim that Ibrahim was Christian, although Christianity came after his time" This is why Allah said,
أَفَلاَ تَعْقِلُونَ
(Have you then no sense)