﴿ وَيَسْـَٔلُونَكَ عَنِ ٱلْمَحِيضِ ۖ قُلْ هُوَ أَذًۭى فَٱعْتَزِلُوا۟ ٱلنِّسَآءَ فِى ٱلْمَحِيضِ ۖ وَلَا تَقْرَبُوهُنَّ حَتَّىٰ يَطْهُرْنَ ۖ فَإِذَا تَطَهَّرْنَ فَأْتُوهُنَّ مِنْ حَيْثُ أَمَرَكُمُ ٱللَّهُ ۚ إِنَّ ٱللَّهَ يُحِبُّ ٱلتَّوَّٰبِينَ وَيُحِبُّ ٱلْمُتَطَهِّرِينَ ﴾

“AND THEY will ask thee about [woman's] monthly courses. Say: "It is a vulnerable condition. Keep, therefore, aloof from women during their monthly courses, and do not draw near unto them until they are cleansed; and when they are cleansed, go in unto them as God has bidden you to do." Verily, God loves those who turn unto Him in repentance and He loves those who keep themselves pure.”

(They question thee (O Muhammad) concerning menstruation) this was revealed about Abu'l-Dahdah who asked the Prophet (pbuh) about it. Allah said to His Prophet: they ask you about sexual intercourse during menstruation, (Say) O Muhammad: (it is harmful) it is filth and unlawful, (so keep away from women at such time) so refrain from having sexual intercourse during menstruation (and go not unto them) do not have sex with them (till they are cleansed) of menstruation. (And when they have purified themselves) and have had a major ritual ablution (ghusl), (then go in unto them) you may have sex with them (as Allah hath enjoined upon you) as you were dispensed to do before, i.e. penetration ought to be in the pudendum. (Truly Allah loveth those who turn unto Him) those who repent of transgression (and loveth those who have a care for cleanness) those who have a care for turning away from transgression and filth.