Bahz bin Hakim narrated from his father that his grandfather said:
"I said: 'O Messenger of Allah, with regard to our 'Awrah, what may we uncover of it and what must we conceal?' He said: 'Cover your 'Awrah, except from your wife and those whom your right hand possesses.' I said: 'O Messenger of Allah, what if the people live close together?' He said: 'If you can make sure that no one sees it, then do not let anyone see it.' I said: 'O Messenger of Allah, what if one of us is alone?' He said: 'Allah is more deserving that you should feel shy before Him than People.' "
English reference: Vol. 3, Book 9, Hadith 1920
Arabic reference: Book 9, Hadith 1995