Al-Adab Al-Mufrad, Book 32, Hadith 7 (In-Book) ⓘ
Sa'd ibn Abi Waqqas transmitted that the Prophet, may Allah bless him and grant him peace, said to him, "You do not spend anything by which you desire the face of Allah Almighty but that you art rewarded for it, even what you place in your wife's mouth."
حَدَّثَنَا أَبُو الْيَمَانِ، قَالَ: حَدَّثَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ قَالَ: حَدَّثَنِي عَامِرُ بْنُ سَعْدٍ، عَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ أَنَّهُ أَخْبَرَهُ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ لِسَعْدٍ: إِنَّكَ لَنْ تُنْفِقَ نَفَقَةً تَبْتَغِي بِهَا وَجْهَ اللهِ عَزَّ وَجَلَّ إِلاَّ أُجِرْتَ بِهَا، حَتَّى مَا تَجْعَلُ فِي فَمِ امْرَأَتِكَ.
also referenced under: Hadith 752 (Reference) & Book 32, Hadith 752 (English)