Sahih al-Bukhari 193
Book 4: Ablutions (Wudu') · Narrated by 'Abdullah bin 'Umar
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، قَالَ أَخْبَرَنَا مَالِكٌ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ قَالَ كَانَ الرِّجَالُ وَالنِّسَاءُ يَتَوَضَّئُونَ فِي زَمَانِ رَسُولِ اللَّهِ صلى الله عليه وسلم جَمِيعًا.
English translation
Narrated 'Abdullah bin 'Umar:"During the lifetime of Allah's Messenger (ﷺ) men and women used to perform ablution together
Reference: Sahih al-Bukhari 193, Book of Ablutions (Wudu'). English translation by Dr. Muhammad Muhsin Khan.