Language:
كتاب النكاح
67  
Wedlock, Marriage (Nikaah)
(72)
Chapter: To accept the invitation to a Walima
(71)
باب حَقِّ إِجَابَةِ الْوَلِيمَةِ وَالدَّعْوَةِ
Sahih al-Bukhari 5176

Narrated Sahl bin Sa`d:

Abu Usaid As-Sa'di invited Allah's Messenger (ﷺ) to his wedding party and his wife who was the bride, served them on that day. Do you know what drink she gave Allah's Messenger (ﷺ)? She had soaked some dates for him (in water) overnight, and when he had finished his meal she gave him that drink (of soaked dates).

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ أَبِي حَازِمٍ، عَنْ أَبِي حَازِمٍ، عَنْ سَهْلِ بْنِ سَعْدٍ، قَالَ دَعَا أَبُو أُسَيْدٍ السَّاعِدِيُّ رَسُولَ اللَّهِ صلى الله عليه وسلم فِي عُرْسِهِ، وَكَانَتِ امْرَأَتُهُ يَوْمَئِذٍ خَادِمَهُمْ وَهْىَ الْعَرُوسُ، قَالَ سَهْلٌ تَدْرُونَ مَا سَقَتْ رَسُولَ اللَّهِ صلى الله عليه وسلم أَنْقَعَتْ لَهُ تَمَرَاتٍ مِنَ اللَّيْلِ، فَلَمَّا أَكَلَ سَقَتْهُ إِيَّاهُ‏.‏
Reference : Sahih al-Bukhari 5176
In-book reference : Book 67, Hadith 111
USC-MSA web (English) reference : Vol. 7, Book 62, Hadith 105
  (deprecated numbering scheme)