Sahih al-Bukhari, Volume 3, Book 34, Hadith 280 (USC-MSA) ⓘ
Narrated Abu Huraira: The Prophet said, "If a woman gives something (i.e. in charity) from her husband's earnings without his permission, she will get half his reward."
حَدَّثَنِي يَحْيَى بْنُ جَعْفَرٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، عَنْ مَعْمَرٍ، عَنْ هَمَّامٍ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " إِذَا أَنْفَقَتِ الْمَرْأَةُ مِنْ كَسْبِ زَوْجِهَا عَنْ غَيْرِ أَمْرِهِ، فَلَهُ نِصْفُ أَجْرِهِ " .
also referenced under: Book 34, Hadith 19 (In-Book) & Hadith 2066 (DarusSalam)