the Fatwa Department Research Committee - chaired by Sheikh `Abd al-Wahhâb al-Turayrî
Abu Shurayh al-`Adawî relates that the Prophet said, "Whoever believes in Allah and the Last Day should honor his neighbor. And whoever believes in Allah and the Last Day should honor his guest and give him his due."
It was asked, "Messenger of Allah, what is his due?"
He said, "His due is a day and, and he should entertain his guest for three days. Whatever exceeds that is charity for him.
And whoever believes in Allah and the Last Day should speak a good word or remain silent." [Sahîh al-Bukhârî (5560)]
Scholars differ regarding what is meant by this "due". Some say it refers to giving the guest the best food and hospitality for that first day. During the other days, the hospitality should be according to the norms of the household.
Scholars who hold this view differ as to whether the first day is inclusive in the three or if the three days are additional to it. Al-Khattâbî and many others regard the hadîth to refer to three days in total.
Other scholars say the due is something unrelated to the hospitality. It is to give the guest provisions of a day and night when he continues on his journey. The hospitality is for the guest to be able to stay for three days.
This is in accordance with some narrations of the hadîth which read: "His hospitality is for three days, and his due is a day and a night."
Ibn Hajar al-Asqalânî gives the following interpretation in Fath al-Bârî (17/324):
The hadîth could be describing two different situations. A traveler sometimes intends to stay at the house. This does not have to be for more than three days. With the first day being better. In other cases, a traveler does not intend to stay the night. In this case, he should be given provisions for a day and a night. This could be the most balanced interpretation.
This shows us that three days is the minimum recommendation for entertaining a guest. Doing so for longer is commendable as charity, but it is not to be regarded as the host's duty.
Of course, individual circumstances need to be taken into consideration, and the host should act according to his or her best discretion and judgment.
And Allah knows best.
Source: Islam Today