"My father narrated to me from my grandfather, who said: 'I said: "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."  

قُلْتُ يَا رَسُولَ اللَّهِ عَوْرَاتُنَا مَا نَأْتِي مِنْهَا وَمَا نَذَرُ قَالَ احْفَظْ عَوْرَتَكَ إِلاَّ مِنْ زَوْجَتِكَ أَوْ مِمَّا مَلَكَتْ يَمِينُكَ فَقَالَ الرَّجُلُ يَكُونُ مَعَ الرَّجُلِ قَالَ إِنِ اسْتَطَعْتَ أَنْ لاَ يَرَاهَا أَحَدٌ فَافْعَلْ قُلْتُ وَالرَّجُلُ يَكُونُ خَالِيًا قَالَ فَاللَّهُ أَحَقُّ أَنْ يُسْتَحْيَا مِنْهُ