glance is Ḥarām and leads to Hell. Allah عَزَّوَجَلَّ emphasises in the 30th verse of Sūraĥ An-Nūr (part 18) that men should protect their eyes:
قُلۡ لِّلۡمُؤۡ مِنِیۡنَ یَغُضُّوۡ ا مِنۡ اَ بۡصَارِ ہِمۡ
Command the Muslim men to keep their gaze low.
[Kanz-ul-Īmān (Translation of Quran)] (Part 18, Sūraĥ An-Nūr, verse 30)
Here is a Quranic command for women:
وَ قُلۡ لِّلۡمُؤۡ مِنٰتِ یَغۡضُضۡنَ مِنۡ اَ بۡصَا رِہِنَّ
And command the Muslim women to keep their gaze low.
[Kanz-ul-Īmān (Translation of Quran)] (Part 18, Sūraĥ An-Nūr, verse 31)
1. Sayyidunā Jarīr Bin ‘Abdullāĥ رَضِىَ اللهُ تَعَالٰی عَـنْهُ asked the Beloved and Blessed Prophet صَلَّى الـلّٰـهُ تَـعَـالٰى عَـلَيْـهِ وَاٰلـِهٖ وَسَـلَّم about a sudden glance at a woman, he صَلَّى اللهُ تَعَالٰى عَلَيْهِ وَاٰلِهٖ وَسَلَّم replied, ‘Turn your eyes away.’
(Ṣaḥīḥ Muslim, pp. 1190, Ḥadīš 2159)
The Greatest and Holiest Prophet صَلَّى اللهُ تَعَالٰى عَلَيْهِ وَاٰلِهٖ وَسَلَّم said to Amīr-ul-Mu`minīn, ‘Alī-ul-Murtaḍā, the lion of Allah کَـرَّمَ الـلّٰـهُ تَـعَالٰی وَجۡھَـهُ الۡـکَرِیۡم: After you have cast a glance, do not cast the second glance (i.e. if you suddenly cast an unintentional glance at a woman then turn your eyes away instantly and do not look again) because the first glance is permissible but the second is prohibited. (Sunan Abī Dāwūd, vol. 2, pp. 358, Ḥadīš 2149)