The Messenger of Allah ﷺ said, "Whoever believes in Allah and the Last Day should honor his guest. The special hospitality is for one day and one night, and hospitality in general is for three days. Anything beyond that is charity. It is not permissible for the guest to stay on with his host to the point of causing him hardship."
حدثنا القعنبي عن مالك عن سعيد المقبري
أن رسول الله ﷺ قال من كان يؤمن بالله واليوم الآخر فليكرم ضيفه جائزته يومه وليلته الضيافة ثلاثة أيام وما بعد ذلك فهو صدقة ولا يحل له أن يثوي عنده حتى يحرجه
Bukhari narrated it in the Book of Manners, chapter on honoring the guest and personally attending to him, etc., hadith no. 6135, from the hadith of Malik through this route, and it is found in the Muwatta (Yahya recension) 2/929. Muslim also narrated it, hadith no. 48 after 1726, from the hadith of Saeed Maqburi through this route.