"Or do you have"—He says this to the polytheists—"a book in which you study?" meaning: in which you read.
﴿ام لكم﴾ يَقُولُهُ لِلْمُشْرِكِينَ ﴿كِتَابٌ فِيهِ تَدْرُسُونَ﴾ تقرءون
