Allah, Exalted be His praise, says: "And do not approach them until they become pure. Then when they have purified themselves, come to them from where Allah has commanded you." [Surah al-Baqarah: 222]
And Imam al-Shafi'i (may Allah have mercy on him) said: "It has been said, and Allah knows best, that (yathurna means) they become pure from menstruation, and when they have purified themselves with water."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / Q1481
Sayyiduna Ibn Abbas (may Allah be pleased with them both) said regarding the saying of Allah Almighty, "So keep away from women during menstruation" [Surah al-Baqarah: 222]: Keep away from intercourse with their private parts. And regarding "And do not approach them until they become pure" [Surah al-Baqarah: 222], he said: When they have become pure from the blood and have thoroughly purified themselves with water. Then regarding "Then come to them from where Allah has commanded you" [Surah al-Baqarah: 222], he said: In the private part, and do not go beyond it to anything else; whoever does anything (other than that) has transgressed the limit.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1481
Mujahid (may Allah have mercy on him) said regarding the saying of Allah Almighty, "And do not approach them until they become pure" [Surah al-Baqarah: 222]: Until the blood stops. And regarding "Then when they have purified themselves" [Surah al-Baqarah: 222], he said: When they have taken a ritual bath.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1482
Al-Hasan (may Allah have mercy on him) said regarding the menstruating woman, when she becomes pure from the blood: Her husband should not come to her until she has taken a ritual bath.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1483
Hadith Gradingمحدثین:حسن لغيرهٖ
Hadith Takhrij«حسن لغيرهٖ۔ أخرجه ابن أبي شيبة 1029»
Salim (may Allah have mercy on him) heard al-Hasan (may Allah have mercy on him) say: There is no harm if the husband covers his wife (that is, has intercourse with her) while no water is available, they are on a journey, and the woman has become pure from menstruation, when she has only performed dry ablution (tayammum).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1484
It is reported from Salim and Sulayman bin Yasar (may Allah have mercy on them both) that they were both asked about the menstruating woman: May her husband have intercourse with her when she sees the purity, before she takes a ritual bath? They said: No, not until she takes a ritual bath.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1485
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that a Bedouin came to the Prophet (peace and blessings be upon him) and said: O Messenger of Allah, we stay in sandy terrain for four or five months, and among us there are women in postnatal bleeding, menstruating women and people in a state of major impurity. What do you say about them? He (peace and blessings be upon him) said: "Hold fast to the soil (that is, perform dry ablution, tayammum)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1486