Musnad Ahmad 456:5

Ya'la narrated to us, 'Abd al-Malik narrated to us, from 'Ata', from Zayd ibn Khalid al-Juhani, from the Prophet, may Allah bless him and grant him peace, who said: "Whoever provides food for a fasting person to break his fast, it is written for him [a reward] like his reward, except that nothing is diminished from the reward of the fasting person. And whoever equips a warrior in the way of Allah, or looks after his family in his absence, it is written for him [a reward] like his reward, except that nothing is diminished from the reward of the warrior." And Yazid said: He informed us, except that he said: "Without anything being diminished."