Sunan Ibn Majah 661
سنن ابن ماجه#661SahihIt was narrated from 'Abdur-Rahman bin Abu Sa'eed Al-Khudri from his father that:The Messenger of Allah said: "No woman should look at the nakedness of another woman, and no man should look at the nakedness of another man
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Muslim
In-book reference: 1:395