Sayyiduna Zayd bin Khalid al-Juhani (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever gives a fasting person something to break his fast with will have a reward equal to that of the one who did the deed, without anything being reduced from the fasting person's reward. And whoever equips a fighter, or takes his place in looking after his family, will have a reward like his, without anything being reduced from his reward."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8137