The Messenger of Allah ﷺ said, "Hospitality is for three days, and whatever is given beyond that counts as charity."
أن رسول الله ﷺ قال: الضيافة ثلاثة أيام، فما كان بعد ذلك فهو صدقة.
Ahmad (11615) and Bazzar - Kashf Astar (1931-1932) both narrated it through various routes from Hammad (that is, Ibn Salama), from Qatada and Saeed (Jareeri), from Abu Nadra, from Abu Saeed Khudri, who related it.Its chain of transmission is sahih.