Wa alaikum assalaam sister,
The two sources of legislation for our faith, are the Qur'an and sunnah (as recorded in the authentic hadeeth). See the following hadeeth of the Prophet (peace and blessings of Allah be upon him):
Narrated `Aisha (may Allah be pleased with her):
The Prophet (may the peace and blessings of Allaah be upon him) 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
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 ".
Reference : Sahih al-Bukhari 331
In-book reference : Book 6, Hadith 35
USC-MSA web (English) reference : Vol. 1, Book 6, Hadith 327
Hadith - Book of Menstrual Periods - Sahih al-Bukhari - Sunnah.com - Sayings and Teachings of Prophet Muhammad (??? ???? ???? ? ???)
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