وَيَسۡـَٔلُونَكَ عَنِ ٱلۡمَحِيضِۖ قُلۡ هُوَ أَذٗى فَٱعۡتَزِلُواْ ٱلنِّسَآءَ فِي ٱلۡمَحِيضِ وَلَا تَقۡرَبُوهُنَّ حَتَّىٰ يَطۡهُرۡنَۖ فَإِذَا تَطَهَّرۡنَ فَأۡتُوهُنَّ مِنۡ حَيۡثُ أَمَرَكُمُ ٱللَّهُۚ إِنَّ ٱللَّهَ يُحِبُّ ٱلتَّوَّـٰبِينَ وَيُحِبُّ ٱلۡمُتَطَهِّرِينَ
And they ask you about menstruation. Say, "It is harm, so keep away from wives during menstruation. And do not approach them until they are pure. And when they have purified themselves, then come to them from where AllŒh has ordained for you. Indeed, AllŒh loves those who are constantly repentant and loves those who purify themselves."
1- i.e., refrain from sexual intercourse.
2- By taking a complete bath (ghusl).
يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُواْ لَا تَقۡرَبُواْ ٱلصَّلَوٰةَ وَأَنتُمۡ سُكَٰرَىٰ حَتَّىٰ تَعۡلَمُواْ مَا تَقُولُونَ وَلَا جُنُبًا إِلَّا عَابِرِي سَبِيلٍ حَتَّىٰ تَغۡتَسِلُواْۚ وَإِن كُنتُم مَّرۡضَىٰٓ أَوۡ عَلَىٰ سَفَرٍ أَوۡ جَآءَ أَحَدٞ مِّنكُم مِّنَ ٱلۡغَآئِطِ أَوۡ لَٰمَسۡتُمُ ٱلنِّسَآءَ فَلَمۡ تَجِدُواْ مَآءٗ فَتَيَمَّمُواْ صَعِيدٗا طَيِّبٗا فَٱمۡسَحُواْ بِوُجُوهِكُمۡ وَأَيۡدِيكُمۡۗ إِنَّ ٱللَّهَ كَانَ عَفُوًّا غَفُورًا
O you who have believed, do not approach prayer while you are intoxicated until you know what you are saying or in a state of janŒbah, except those passing through [a place of prayer], until you have washed [your whole body]. And if you are ill or on a journey or one of you comes from the place of relieving himself or you have contacted women [i.e., had sexual intercourse] and find no water, then seek clean earth and wipe over your faces and your hands [with it]. Indeed, AllŒh is ever Pardoning and Forgiving.
1- The use of intoxicants was later prohibited completely. See 5:90-91.
2- Literally, "distance." The state of one under obligation to perform ghusl (a complete bath) due to having had sexual intercourse or ejaculation.
3- Literally, able to erase and remove sins completely, leaving no trace of them in the record of deeds.