Sahih al-Bukhari 56
Sahih al-Bukhari · Book 2: Belief · What is said regarding the statement: "The reward of deeds depends upon the intention and hoping to get rewards from Allah."
Narrated Sa'd bin Abi Waqqas:
حَدَّثَنَا الْحَكَمُ بْنُ نَافِعٍ قَالَ أَخْبَرَنَا شُعَيْبٌ عَنْ الزُّهْرِيِّ قَالَ حَدَّثَنِي عَامِرُ بْنُ سَعْدٍ عَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ أَنَّهُ أَخْبَرَهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ " إِنَّكَ لَنْ تُنْفِقَ نَفَقَةً تَبْتَغِي بِهَا وَجْهَ اللَّهِ إِلَّا أُجِرْتَ عَلَيْهَا حَتَّى مَا تَجْعَلُ فِي فَمِ امْرَأَتِكَ"
Allah's Messenger (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."