Sahih al-Bukhari 4259
Sahih al-Bukhari · Book 64: Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi) · ‘'Umra Al-Qada’
Ibn `Abbas added:
وَزَادَ ابْنُ إِسْحَاقَ حَدَّثَنِي ابْنُ أَبِي نَجِيحٍ ، وَأَبَانُ بْنُ صَالِحٍ ، عَنْ عَطَاءٍ ، وَمُجَاهِدٍ ، عَنِ ابْنِ عَبَّاسٍ ، قَالَ تَزَوَّجَ النَّبِيُّ صلى الله عليه وسلم مَيْمُونَةَ فِي عُمْرَةِ الْقَضَاءِ .
The Prophet married Maimuna during the `Umrat-al-Qada' (i.e. the `Umra performed in lieu of the `Umra which the Prophet (ﷺ) could not perform because the pagans, prevented him to perform that `Umra).