Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) narrates: I prepared food for the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) came to me with his Companions (may Allah be pleased with them). When the food was set down, a man among the people said: I am fasting. The Messenger of Allah (peace and blessings be upon him) said: "Your brother has invited you and gone to trouble for you." Then he said to him: "Break your fast, and fast a day in its place if you wish."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8362