Imam Malik's Muwatta, Chapter: The Description of the Prophet, may Allah Bless Him and Grant Him Peace

Yahya related to me from Malik from Said ibn Abi Said al-Maqburi from Abu Shurayh al-Kabi that the Messenger of Allah, may Allah bless him and grant him peace, said, "Whoever believes in Allah and the Last Day should speak good or be silent. Whoever believes in Allah and the Last Day should be generous to his neighbour. Whoever believes in Allah and the Last Day, should be generous to his guest. His welcome is for a day and a night, and his hospitality is for three days. Whatever is more than that is sadaqa. It is not halal for a guest to stay with a man until he becomes a burden."