Messenger of Allah ﷺ said, "You will be rewarded for whatever you spend for Allah's sake even if it were a morsel which you put in your wife's mouth." (Using translation from Bukhārī 56)  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ يَا سَعْدُ «إِنَّكَ لَنْ تُنْفِقَ نَفَقَةً تَبْتَغِي بِهَا وَجْهَ اللهِ إِلَّا أُجِرْتَ عَلَيْهَا حَتَّى اللُّقْمَةِ تَجْعَلُهَا فِي فِيِّ امْرَأَتِكَ»  

[Machine] The Prophet ﷺ said, "Indeed, whatever you spend of expenses, it is considered a charity until even the morsel you raise to your wife's mouth."  

قَالَ النَّبِيُّ ﷺ «إِنَّكَ مَهْمَا أَنْفَقْتَ مِنْ نَفَقَةٍ فَإِنَّهَا صَدَقَةٌ حَتَّى اللُّقْمَةِ تَرْفَعُهَا إِلَى فِيِّ امْرَأَتِكَ»