Sayyiduna Abu Mas'ud (may Allah be pleased with him) said: A man from the Ansar called Abu Shu'ayb said to his slave, who was a butcher: "Prepare enough food for me for five men, for I have seen (the signs of) hunger on the face of the Messenger of Allah (peace and blessings be upon him)." So he prepared the food for him. Then he sent for the Prophet (peace and blessings be upon him) and those companions of his who were sitting with him. When the Prophet (peace and blessings be upon him) stood up, a man followed them who had not been with them when they were invited. When they reached the door, he (peace and blessings be upon him) said to the host: "A man has followed me who was not present when you invited us. If you permit him, he will come in." He said: "We have permitted him; let him come in."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14603