Head Coverings
وَقُلْ لِلْمُؤْمِنَاتِ يَغْضُضْنَ مِنْ أَبْصَارِهِنَّ وَيَحْفَظْنَ فُرُوجَهُنَّ وَلَا يُبْدِينَ زِينَتَهُنَّ إِلَّا مَا ظَهَرَ مِنْهَا ۖ وَلْيَضْرِبْنَ بِخُمُرِهِنَّ عَلَىٰ جُيُوبِهِنَّ ۖ وَلَا يُبْدِينَ زِينَتَهُنَّ إِلَّا لِبُعُولَتِهِنَّ أَوْ آبَائِهِنَّ أَوْ آبَاءِ بُعُولَتِهِنَّ أَوْ أَبْنَائِهِنَّ أَوْ أَبْنَاءِ بُعُولَتِهِنَّ أَوْ إِخْوَانِهِنَّ أَوْ بَنِي إِخْوَانِهِنَّ أَوْ بَنِي أَخَوَاتِهِنَّ أَوْ نِسَائِهِنَّ أَوْ مَا مَلَكَتْ أَيْمَانُهُنَّ أَوِ التَّابِعِينَ غَيْرِ أُولِي الْإِرْبَةِ مِنَ الرِّجَالِ أَوِ الطِّفْلِ الَّذِينَ لَمْ يَظْهَرُوا عَلَىٰ عَوْرَاتِ النِّسَاءِ ۖ وَلَا يَضْرِبْنَ بِأَرْجُلِهِنَّ لِيُعْلَمَ مَا يُخْفِينَ مِنْ زِينَتِهِنَّ ۚ وَتُوبُوا إِلَى اللَّهِ جَمِيعًا أَيُّهَ الْمُؤْمِنُونَ لَعَلَّكُمْ تُفْلِحُونَ {31}
And say to the Mominaat to cast down their eyes and preserve their private parts and not to display their adornments except what is apparent from these. And let them place ‘بِخُمُرِهِنَّ’ their scarves upon their bosoms. And they should not display their adornments except to their husbands, or their fathers, or fathers of their husbands, or their sons, or sons of their husbands, or their brothers, or sons of their brothers, or sons of their sisters, or their womenfolk, or what their right hands possess, or servants without being nourished from the men, or the children, those not having been exposed to the private parts of the women, and they should not strike with their legs for it to be known what is hidden from their adornments. And repent to Allah altogether, O Momineen, perhaps you will succeed [24:31]
وعنه: عن علي بن إبراهيم، عن أبيه، عن بكر بن صالح، عن القاسم بن بريد، قال: حدثنا أبو عمرو الزبيري، عن أبي عبد الله (عليه السلام)- في حديث- قال: «و فرض الله على البصر أن لا ينظر إلى ما حرم الله عليه، و أن يعرض عما نهى الله عنه مما لا يحل له، و هو عمله، و هو من الإيمان، قال الله تبارك و تعالى: قُلْ لِلْمُؤْمِنِينَ يَغُضُّوا مِنْ أَبْصارِهِمْ وَ يَحْفَظُوا فُرُوجَهُمْ فنهاهم أن ينظروا إلى عوراتهم، و أن ينظر المرء إلى فرج أخيه، و يحفظ فرجه أن ينظر إليه
And from him, from Ali Bin Ibrahim, from his father, from Bakr Bin Salih, from Al Qasim Bin Bureyd, from Abu Amro Al-Zubeyri, who has said:
(It has been narrated) from Abu Abdullah-asws – in a Hadeeth – having said: ‘And Allah-azwj has Necessitated upon the vision it should not look at what Allah-azwj has Forbidden to it, and that he should turn away from what Allah-azwj has Prohibited from it, that which is not Permissible for it. And it is his deed, and it is from the Eman (Belief). Allah-azwj Blessed and High Says [24:30] Say to the believing men that they should cast down their looks and guard their private parts; that is purer for them; surely Allah is Aware of what they are doing.
So, Allah-azwj has Prohibited them from looking at their nakedness, from a person to not look at the private parts of his brother, and he should protect his private parts from being looked at.
و قال: وَ قُلْ لِلْمُؤْمِناتِ يَغْضُضْنَ مِنْ أَبْصارِهِنَّ وَ يَحْفَظْنَ فُرُوجَهُنَّ من أن تنظر إحداهن إلى فرج أختها، و تحفظ فرجها من أن ينظر إليها- و قال- كل شيء في القرآن من حفظ الفرج فهو من الزنا، إلا هذه الآية، فإنها من النظر
And Allah-azwj Says: And say to the believing women that they should cast down their looks and guard their private parts [24:31], from one of them not to look at the private parts of her sister, and protect her private parts from being looked at. And he-asws (the Imam-asws) said: ‘Everything in the Quran, from the protection of the private parts, is to do with the adultery, except for this Verse, for it is to do with the looking’.[1]
NB: https://hubeali.com/hijab-for-women-men/
[1] الكافي 2: 30/ 1.