﴿ وَكَذَٰلِكَ أَوْحَيْنَآ إِلَيْكَ رُوحًۭا مِّنْ أَمْرِنَا ۚ مَا كُنتَ تَدْرِى مَا ٱلْكِتَٰبُ وَلَا ٱلْإِيمَٰنُ وَلَٰكِن جَعَلْنَٰهُ نُورًۭا نَّهْدِى بِهِۦ مَن نَّشَآءُ مِنْ عِبَادِنَا ۚ وَإِنَّكَ لَتَهْدِىٓ إِلَىٰ صِرَٰطٍۢ مُّسْتَقِيمٍۢ ﴾

“And thus, too, [O Muhammad,] have We revealed unto thee a life-giving message, [coming] at Our behest. [Ere this message came unto thee,] thou didst not know what revelation is, nor what faith [implies]: but [now] We have caused this [message] to be a light, whereby We guide whom We will of Our ser­vants: and, verily, [on the strength thereof] thou, too, shalt guide [men] onto the straight way –”

Please check ayah 42:53 for complete tafsir.