Risālat al-Ḥuqūq
Hadith 6وَأَمَّا حَقُّ بَصَرِكَ أن تُغْمِضَهُ عَمَّا لا يَحِلُّ لَكَ و تَعْتَبِر بالنَّظَرِ بِهِ.
The right of sight is that you lower it before everything which is unlawful to you and that you take heed whenever you look at anything. [1]