Surah al-Talaq

It is narrated from Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) that when that verse of Surah al-Baqarah was revealed in which the waiting period ('iddah) of women is stated, the people said: "Some kinds of women's waiting periods still remain which have not been mentioned: namely the young girls whose menstruation has not yet begun, the elderly women whose menstruation has stopped because of old age, and pregnant women." Then Allah Almighty revealed this verse of the shorter Surah al-Nisa' (Surah al-Talaq): "And those of your women who have despaired of menstruation, if you are in doubt, their waiting period is three months, and (the same applies to) those who have not menstruated; and as for those who are pregnant, their term is until they deliver their child" [Surah al-Talaq: 4]. In another narration from Amr bin Salim it is stated that when the verse concerning the waiting period of the divorced woman and the widow was revealed in Surah al-Baqarah, Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) said: "O Messenger of Allah (peace and blessings be upon him)!" Then he mentioned something similar to the previous narration.
Takhrij and grading: Ishaq bin Rahwayh recorded it from Jarir, and Yahya bin Adam from al-Mufaddal bin Muhalhal, both through Mutarrif bin Tarif from Amr bin Salim. This report provides a reliable explanation of the background and occasion of revelation of the fourth verse of Surah al-Talaq.

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both), explaining the saying of Allah Almighty "And they should not go out unless they commit a clear immorality" [Surah al-Talaq: 1], says: "'Clear immorality' means that she (the divorced woman, during her waiting period) is foul-mouthed and insolent towards her in-laws; so when she does that (adopts such improper conduct), it becomes lawful and permissible for them to put her out (of the house)."
The chain of this report is hasan (good), and Imam al-Nasa'i recorded it in al-Sunan al-Kubra.