It was narrated that Anas said:

"When the 'Iddah of Zainab was over, the Messenger of Allah said to Zaid: 'Propose marriage to her on my behalf.' Zaid went and said: 'O Zainab, rejoice, for the Messenger of Allah has sent me to you to propose marriage on his behalf.' She said: 'I will not do anything until I consult my Lord.' She went to her prayer place and Qur'an was revealed, then the Messenger of Allah came and entered upon her without any formalities."

أَخْبَرَنَا سُوَيْدُ بْنُ نَصْرٍ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، قَالَ حَدَّثَنَا سُلَيْمَانُ بْنُ الْمُغِيرَةِ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ، قَالَ لَمَّا انْقَضَتْ عِدَّةُ زَيْنَبَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لِزَيْدٍ ‏

‏ اذْكُرْهَا عَلَىَّ ‏

‏ ‏.‏ قَالَ زَيْدٌ فَانْطَلَقْتُ فَقُلْتُ يَا زَيْنَبُ أَبْشِرِي أَرْسَلَنِي إِلَيْكِ رَسُولُ اللَّهِ صلى الله عليه وسلم يَذْكُرُكِ ‏.‏ فَقَالَتْ مَا أَنَا بِصَانِعَةٍ شَيْئًا حَتَّى أَسْتَأْمِرَ رَبِّي فَقَامَتْ إِلَى مَسْجِدِهَا وَنَزَلَ الْقُرْآنُ وَجَاءَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَدَخَلَ بِغَيْرِ أَمْرٍ ‏.‏