Sunan an-Nasa'i, Volume 4, Book 27, Hadith 3546 (DarusSalam) ⓘ

It was narrated from Abu Salamah bin 'Abdur-Rahman that Zainab bint Abi Salamah told him, from her mother, Umm Salamah, the wife of the Prophet: "That a woman from Aslam who was called Subai'ah was married to her husband, and he died while she was pregnant. Abu As-Sanabil bin Ba'kak proposed to her but she refused to marry him. He said: 'You cannot get married until you have observed 'Iddah for the longer of the two periods.' Approximately twenty days later she gave birth. She went to the Messenger of Allah and he said: 'Get married.'"

أَخْبَرَنَا عَبْدُ الْمَلِكِ بْنُ شُعَيْبِ بْنِ اللَّيْثِ بْنِ سَعْدٍ، قَالَ حَدَّثَنِي أَبِي، عَنْ جَدِّي، قَالَ حَدَّثَنِي جَعْفَرُ بْنُ رَبِيعَةَ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ هُرْمُزَ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، أَنَّ زَيْنَبَ بِنْتَ أَبِي سَلَمَةَ، أَخْبَرَتْهُ عَنْ أُمِّهَا أُمِّ سَلَمَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّ امْرَأَةً مِنْ أَسْلَمَ يُقَالُ لَهَا سُبَيْعَةُ كَانَتْ تَحْتَ زَوْجِهَا فَتُوُفِّيَ عَنْهَا وَهِيَ حُبْلَى فَخَطَبَهَا أَبُو السَّنَابِلِ بْنُ بَعْكَكٍ فَأَبَتْ أَنْ تَنْكِحَهُ فَقَالَ مَا يَصْلُحُ لَكِ أَنْ تَنْكِحِي حَتَّى تَعْتَدِّي آخِرَ الأَجَلَيْنِ ‏.‏ فَمَكَثَتْ قَرِيبًا مِنْ عِشْرِينَ لَيْلَةً ثُمَّ نُفِسَتْ فَجَاءَتْ رَسُولَ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏ "‏ انْكِحِي ‏" ‏ ‏.‏