Sura al-Baqara 2:222

وَيَسْـَٔلُونَكَ عَنِ ٱلْمَحِيضِ قُلْ هُوَ أَذًى فَٱعْتَزِلُوا۟ ٱلنِّسَآءَ فِى ٱلْمَحِيضِ وَلَا تَقْرَبُوهُنَّ حَتَّىٰ يَطْهُرْنَ فَإِذَا تَطَهَّرْنَ فَأْتُوهُنَّ مِنْ حَيْثُ أَمَرَكُمُ ٱللَّـهُ إِنَّ ٱللَّـهَ يُحِبُّ ٱلتَّوَّٰبِينَ وَيُحِبُّ ٱلْمُتَطَهِّرِينَ

wa-yasʾalūnaka ʿani l-maḥīḍi qul huwa adhan faʿtazilū l-nisāʾa fī l-maḥīḍi wa-lā taqrabūhunna ḥattā yaṭhurna fa-idhā taṭahharna fatūhunna min ḥaythu amarakumu allāhu inna allāha yuḥibbu l-tawwābīna wa-yuḥibbu l-mutaṭahhirīna

They ask thee concerning women's courses. Say: They are a hurt and a pollution: So keep away from women in their courses, and do not approach them until they are clean. But when they have purified themselves, ye may approach them in any manner, time, or place ordained for you by Allah. For Allah loves those who turn to Him constantly and He loves those who keep themselves pure and clean.