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."  

أَنَّهُ أَخْبَرَهُ أَنَّ النَّبِيَّ ﷺ قَالَ لِسَعْدٍ إِنَّكَ لَنْ تُنْفِقَ نَفَقَةً تَبْتَغِي بِهَا وَجْهَ اللهِ عَزَّ وَجَلَّ إِلاَّ أُجِرْتَ بِهَا حَتَّى مَا تَجْعَلُ فِي فَمِ امْرَأَتِكَ