Surah Ash-Shura (The Consultation), Verse 52

وَكَذٰلِكَ اَوْحَیْنَاۤ اِلَیْكَ رُوْحًا مِّنْ اَمْرِنَا مَا كُنْتَ تَدْرِیْ مَا الْكِتٰبُ وَلَا الْاِیْمَانُ وَلٰكِنْ جَعَلْنٰهُ نُوْرًا نَّهْدِیْ بِهٖ مَنْ نَّشَآءُ مِنْ عِبَادِنَا وَاِنَّكَ لَتَهْدِیْۤ اِلٰی صِرَاطٍ مُّسْتَقِیْمٍ ۟

Wa kazaalika awhainaaa ilaika roohan min amrinaa; maa kunta tadree mal Kitaabu wa lal eemaanu wa laakin ja'alnaahu nooran nahdee bihee man nashaaa'u min 'ibaadinaa; wa innaka latahdeee ilaaa Siraatin Mustaqeem

“And thus have We, by Our Command, sent inspiration to thee: thou knewest not (before) what was Revelation, and what was Faith; but We have made the (Qur'an) a Light, wherewith We guide such of Our servants as We will; and verily thou dost guide (men) to the Straight Way,-”

Quran 42:52 (Yusuf Ali Translation)