Sayyiduna Zayd bin Khalid (may Allah be pleased with him) narrated that the Prophet (peace and blessings be upon him) said: "Whoever gives a fasting person something to break his fast with, or equips a fighter, will have a reward equal to his reward."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8140