Musnad Ahmad 939:4

Yahya ibn Sa'id narrated to us, from 'Abd al-Malik, 'Ata' narrated to us, from Zayd ibn Khalid al-Juhani, from the Prophet, peace and blessings of Allah be upon him: "Whoever provides food for a fasting person to break his fast, there shall be for him—or it shall be written for him—the like of the reward of the fasting person, without anything being diminished from the reward of the fasting person. And whoever equips a warrior in the way of Allah, there shall be for him—or it shall be written for him—the like of the reward of the warrior, in that nothing is diminished from the reward of the warrior."