Tell the believing men to reduce [some] of their vision1 and guard their private parts.2 That is purer for them. Indeed, Allāh is [fully] Aware of what they do.
Translation: Saheeh International (English)
1 Looking only at what is lawful and averting their eyes from what is unlawful.
O Messenger, tell the believing men to stop their eyes from looking at women and private parts that are unlawful for them, and to protect their private parts from indulging in the unlawful and from exposing them. That refraining from looking at what Allah has made unlawful is purer for them in the sight of Allah. Allah is Aware of what you do.