Muwatta Malik 1245

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنِ الْمِسْوَرِ بْنِ مَخْرَمَةَ، أَنَّهُ أَخْبَرَهُ أَنَّ سُبَيْعَةَ الأَسْلَمِيَّةَ نُفِسَتْ بَعْدَ وَفَاةِ زَوْجِهَا بِلَيَالٍ فَقَالَ لَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ قَدْ حَلَلْتِ فَانْكِحِي مَنْ شِئْتِ ‏"‏ ‏.‏

Yahya related to me from Malik from Hisham ibn 'Urwa from his father that al-Miswar ibn Makhrama told him that Subaya al-Aslamiya gave birth a few nights after the death of her husband. The Messenger of Allah, may Allah bless him and grant him peace, said to her, "You are free to marry, so marry whomever you wish

Reference

Muwatta Malik 1245

In-book

Book 29, Hadith 42