Surah Ad-Dukhan, Verse 3

إِنَّآ أَنزَلۡنَٰهُ فِي لَيۡلَةٖ مُّبَٰرَكَةٍۚ إِنَّا كُنَّا مُنذِرِينَ٣

innā anzalnāhu fī laylatin mubārakatin innā kunnā mundhirīna

Indeed, We sent it down during a blessed night. Indeed, We were to warn [mankind].