Surah An-Nur, ayah 30

قُل لِّلۡمُؤۡمِنِينَ يَغُضُّواْ مِنۡ أَبۡصَٰرِهِمۡ وَيَحۡفَظُواْ فُرُوجَهُمۡۚ ذَٰلِكَ أَزۡكَىٰ لَهُمۡۚ إِنَّ ٱللَّهَ خَبِيرُۢ بِمَا يَصۡنَعُونَ ٣٠

Qul lil-mu'minīna yaghuddū min absārihim wayahfazū furūjahum dhālika azkā lahum innallāha khabīru bimā yasna'ūn

Tell the believing men to reduce [some] of their vision⁹⁸⁸ and guard their private parts.⁹⁸⁹ That is purer for them. Indeed, Allāh is [fully] Aware of what they do.