'A'isha reported that the wives of Messenger of Allah ﷺ used to go out in the cover of night when they went to open fields (in the outskirts of Medina) for easing themselves. 'Umar b Khattab used to say: Allah's Messenger, ask your ladies to observe veil, but Messenger of Allah ﷺ did not do that. So there went out Sauda, daughter of Zarn'a, the wife of Messenger of Allah ﷺ, during one of the nights when it was dark. She was a tall statured lady. 'Umar called her saying: Sauda, we recognise you. (He did this with the hope that the verses pertaining to veil would be revealed.) 'A'isha said: Allah, the Exalted and Glorious, then revealed the verses pertaining to veil.

حَدَّثَنَا عَبْدُ الْمَلِكِ بْنُ شُعَيْبِ بْنِ اللَّيْثِ، حَدَّثَنِي أَبِي، عَنْ جَدِّي، حَدَّثَنِي عُقَيْلُ بْنُ، خَالِدٍ عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ، عَنْ عَائِشَةَ، أَنَّ أَزْوَاجَ، رَسُولِ اللَّهِ ﷺ كُنَّ يَخْرُجْنَ بِاللَّيْلِ إِذَا تَبَرَّزْنَ إِلَى الْمَنَاصِعِ وَهُوَ صَعِيدٌ أَفْيَحُ وَكَانَ عُمَرُ بْنُ الْخَطَّابِ يَقُولُ لِرَسُولِ اللَّهِ ﷺ احْجُبْ نِسَاءَكَ . فَلَمْ يَكُنْ رَسُولُ اللَّهِ ﷺ يَفْعَلُ فَخَرَجَتْ سَوْدَةُ بِنْتُ زَمْعَةَ زَوْجُ النَّبِيِّ ﷺ لَيْلَةً مِنَ اللَّيَالِي عِشَاءً وَكَانَتِ امْرَأَةً طَوِيلَةً فَنَادَاهَا عُمَرُ أَلاَ قَدْ عَرَفْنَاكِ يَا سَوْدَةُ . حِرْصًا عَلَى أَنْ يُنْزِلَ الْحِجَابَ . قَالَتْ عَائِشَةُ فَأَنْزَلَ اللَّهُ عَزَّ وَجَلَّ الْحِجَابَ .