Jami` at-Tirmidhi, Volume 2, Book 10, Hadith 1154 (DarusSalam)

Aishah narrated: “Barfah’s husband was a slave, so the Messenger of Allah let her chose, and she chose herself, and if he was a free man she would not have had a choice.”

حَدَّثَنَا عَلِيُّ بْنُ حُجْرٍ، أَخْبَرَنَا جَرِيرُ بْنُ عَبْدِ الْحَمِيدِ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ كَانَ زَوْجُ بَرِيرَةَ عَبْدًا فَخَيَّرَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَاخْتَارَتْ نَفْسَهَا وَلَوْ كَانَ حُرًّا لَمْ يُخَيِّرْهَا ‏.‏

sunnah.com