It is narrated from Sayyida Aisha (may Allah be pleased with her) that she said: When Hafsa bint Abdur Rahman entered her third menstrual period, she changed her residence. Ibn Shihab (may Allah have mercy on him) said: I mentioned this matter to Amrah bint Abdur Rahman, and she said: "Urwah has spoken the truth. In fact, people objected to Aisha (may Allah be pleased with her), saying: Allah Almighty says: 'Divorced women shall keep themselves in waiting for three periods (__QUR_N__),' so Aisha (may Allah be pleased with her) said: You have spoken the truth. Do you know what is meant by 'qurūʼ'? 'Qurūʼ' means purity."
Hadith Referenceمسند الإمام الشافعي / كتاب العدد والسكنى والنفقات / 1288
Hadith Takhrijاسناده صحیح اخرجه البيهقي : 415/7 - وفى المعرفة السنن والآثار له (4604)۔ وعبد الرزاق (11004)۔ ومالك في الموطأ الطلاق، باب ما جاء في الاقراء وعدة الطلاق وطلاق الحائض۔