Assalamualaikum ustaz. What is the ruling for performing ablution naked? Hope for an answer. Thank you.
Waalaikumussalam wrt. wbt.,
Alhamdulillah, praise and gratitude to Allah SWT for His countless blessings for us all. Praise and salutations to our beloved Prophet Muhammad PBUH, his family, companions, and all those who follow his footsteps until the Final day.
We’ll begin with Allah SWT’s statement:
يَا أَيُّهَا الَّذِينَ آمَنُوا إِذَا قُمْتُمْ إِلَى الصَّلَاةِ فَاغْسِلُوا وُجُوهَكُمْ وَأَيْدِيَكُمْ إِلَى الْمَرَافِقِ وَامْسَحُوا بِرُءُوسِكُمْ وَأَرْجُلَكُمْ إِلَى الْكَعْبَيْنِ
“O you who have believed, when you rise to [perform] prayer, wash your faces and your forearms to the elbows and wipe over your heads and wash your feet to the ankles.” 
Al-Maraghi stated that the meaning of the above verse is that if a person gets up to pray – but is still in hadas. The reason is all Muslims state that purification (ablution or obligatory bath) isn’t obligatory for those who wanted to pray except if he is in hadas (impure state). 
Likewise, Al-Sa’di said there are numerous ruling questions (that can be extracted) from this verse. Among them is the commandment to perform the prayer, setting the intention for prayer, as well as the valid condition of prayer is purification (from hadas), and purification is not obligated when the time for prayer begins but it is obligatory when one wants to pray and others. 
The definition ablution
Originates from the word wadha’ah (وَضَاءَةٌ). Lexically, it means proper and beautiful. While according to syarak, it is the act of washing certain body parts preceded with the intention. It is named as such because it is an act of bettering and beautifying the body parts washed and cleaned. 
Coming back to the questions asked, ‘covering aurah when performing ablution’ isn’t stated as the obligatory or sunnah matters. However, in the chapter on taking a bath, covering the aurah is among the sunnah matters. Aurah meant here is the two private parts; the penis/vagina and the anus. Thus, it is sunnah for a person to cover both the private parts when he is alone. 
Although, the ruling is different if a person performs the ablution without wearing anything in a public. The reason is, if this is so, it is clear that it is obligatory for him to cover his aurah. This is based on the hadith from Abu Sa’id al-Khudri where Rasullullah PBUH said:
لَا يَنْظُرُ الرَّجُلُ إِلَى عَوْرَةِ الرَّجُلِ وَلَا تَنْظُرُ الْمَرْأَةُ إِلَى عَوْرَةِ الْمَرْأَةِ
“A man must not look at a man’s private parts or a woman at a woman’s,” 
In another hadith, narrated by Bahz bin Hakim from his father from his grandfather, he said:
قُلْتُ: يَا رَسُولَ اللَّهِ عَوْرَاتُنَا مَا نَأْتِي مِنْهَا وَمَا نَذَرُ؟ قَالَ: «احْفَظْ عَوْرَتَكَ إِلَّا مِنْ زَوْجَتِكَ أَوْ مَا مَلَكَتْ يَمِينُكَ»، فَقَالَ: الرَّجُلُ يَكُونُ مَعَ الرَّجُلِ؟ قَالَ: إِنْ اسْتَطَعْتَ أَنْ لَا يَرَاهَا أَحَدٌ فَافْعَلْ»، قُلْتُ: وَالرَّجُلُ يَكُونُ خَالِيًا، قَالَ: «فَاللَّهُ أَحَقُّ أَنْ يُسْتَحْيَا مِنْهُ
“O Messenger of Allah! Regarding our ‘Awrah, what of it must we cover and what of it may we leave?” He said: “Protect your ‘Awrah except from your wife or what your right hand possesses.”‘ He said: “What about a man with another man?” He said: “If you are able to not let anyone see it, then do so.” I said: “What about a man when he is alone?” He said: “Allah is most deserving of being shy from Him.” 
Furthermore, as Muslims, we should strive to avoid exposing our aurah unnecessarily even when we are alone. This is as cited by the scholars of madhhab Hanafi – according to the sahih opinion – madhhab Syafi’I scholars and scholars of madhhab Hanbali are of the opinion that it is obligatory to cover the aurah even when one is alone (in a secluded place) and far from the view of others. While according to the scholars of madhhab Maliki, it is sunnah to cover one’s aurah when he is alone and it is commanded as being shameful in front of Allah SWT and His angels. Whereas, the jumhur of scholars argued that the commandment to cover the aurah is an absolute commandment and also because Allah SWT is most deserving of being shy in His presence as stated in a hadith of Bahz bin Hakim as stated above. Thus, covering the aurah when one is alone is commanded except if there is a necessity such as to take a bath, cooling off and others. 
The former Saudi Arabia Grand Mufti Syeikh ‘Abd al-‘Aziz once asked whether the ablution of a person is valid if he performs his ablution naked in a place (secluded and alone)? He answered, there is no issue on the matter. However, if he puts on his clothing first, then perform his ablution, then this is better and complete. 
According to the above discussion and deliberation, we conclude that a person who performs his ablution naked in a secluded and enclosed space (and he is alone), his ablution is valid. Likewise, if he performs his ablution in a public place and exposes his aurah, his ablution is also valid. However, he is sinful for exposing his aurah to those who are prohibited from seeing it.
As a Muslim, he should always protect his dignity and doesn’t expose his own misgivings in front of others. Especially when ablution is worship and hence it is better and afdhal to perform it while one’s aurah is covered.
May Allah SWT grant us all a clear understanding in religion. Amin.
 Surah al-Ma’idah: 6
 See Tafsir al-Maraghi, 6/61
 See Tafsir al-Sa‘di, pg. 222
 See al-Fiqh al-Manhaji, 1/53.
 See al-Taqrirat al-Sadidah, pg. 120.
 Narrated by al-Tirmizi (2793)
 Narrated by al-Tirmizi (2769)
 See Mausu‘ah al-Fiqhiyyah al-Kuwaitiyyah, 24/176.
 See https://binbaz.org.sa/fatwas/8021/حكم-الوضوء-والانسان-عريان. Accessed on 31st December 2021.