Sunan Ibn Majah, Book 1, Hadith 400 (In-Book) ⓘ
It was narrated that Ibn 'Abbas said: "One of the wives of the Prophet took a bath from a large vessel, then the Prophet came and had a bath or ablution, and she said: 'O Messenger of Allah, I was sexually impure.' He said: 'Water does not become impure.'"
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ سِمَاكِ بْنِ حَرْبٍ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ اغْتَسَلَ بَعْضُ أَزْوَاجِ النَّبِيِّ ـ صلى الله عليه وسلم ـ فِي جَفْنَةٍ فَجَاءَ النَّبِيُّ ـ صلى الله عليه وسلم ـ لِيَغْتَسِلَ أَوْ يَتَوَضَّأَ فَقَالَتْ يَا رَسُولَ اللَّهِ إِنِّي كُنْتُ جُنُبًا . فَقَالَ " الْمَاءُ لاَ يُجْنِبُ " .
also referenced under: Hadith 370 (Reference) & Volume 1, Book 1, Hadith 370 (DarusSalam)