He who feeds a fasting person will earn the same reward as him (the fasting person), without diminishing anything from the reward of the fasting person
[Ibn Maajah]
Original Hadith
"«مَنْ فَطَّرَ صائمًا، كان له مِثْلُ أجْرِهِ، غَيْرَ أنَّهُ لاَ يُنْقَصُ مِنْ أجْرِ الصَّائِمِ شَيْءٌ».
[صحيح.] - [رواه الترمذي"