Sahih al-Bukhari 331
Sahih al-Bukhari · Book 6: Menstrual Periods · When a woman having bleeding in between her periods notices signs of cleanliness from her menses
Narrated `Aisha:
حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ ، عَنْ زُهَيْرٍ ، قَالَ حَدَّثَنَا هِشَامٌ ، عَنْ عُرْوَةَ ، عَنْ عَائِشَةَ ، قَالَتْ قَالَ النَّبِيُّ صلى الله عليه وسلم " إِذَا أَقْبَلَتِ الْحَيْضَةُ فَدَعِي الصَّلاَةَ، وَإِذَا أَدْبَرَتْ فَاغْسِلِي عَنْكِ الدَّمَ وَصَلِّي " .
The Prophet (ﷺ) said to me, "Give up the prayer when your menses begin and when it has finished, wash the blood off your body (take a bath) and start praying."