Language:
كتاب الزكاة
24  
Obligatory Charity Tax (Zakat)
(25)
Chapter: The servant gets a reward for giving charity when ordered by the owner
(25)
باب أَجْرِ الْخَادِمِ إِذَا تَصَدَّقَ بِأَمْرِ صَاحِبِهِ غَيْرَ مُفْسِدٍ
Sahih al-Bukhari 1437

Narrated `Aisha:

Allah's Messenger (ﷺ) said, "When a woman gives in charity from her husband's meals without wasting the property of her husband, she will get a reward for it, and her husband too will get a reward for what he earned and the storekeeper will have the reward likewise."

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ أَبِي وَائِلٍ، عَنْ مَسْرُوقٍ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ إِذَا تَصَدَّقَتِ الْمَرْأَةُ مِنْ طَعَامِ زَوْجِهَا غَيْرَ مُفْسِدَةٍ كَانَ لَهَا أَجْرُهَا، وَلِزَوْجِهَا بِمَا كَسَبَ، وَلِلْخَازِنِ مِثْلُ ذَلِكَ ‏"‏‏.‏
Reference : Sahih al-Bukhari 1437
In-book reference : Book 24, Hadith 40
USC-MSA web (English) reference : Vol. 2, Book 24, Hadith 518
  (deprecated numbering scheme)