Jami` at-Tirmidhi 1968
جامع الترمذي#1968SahihAbu Shuraih Al-Kabi narrated that the Messenger of Allah said:: "Hospitality is for three days, and his reward is a day and a night, and whatever is spent on him after that is charity. And it is not lawful for him (the guest) to stay so long as to cause him harm
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih
In-book reference: 27:74