He who believes in Allah and the Last Day should honour his guest provisions for the road are what will serve for a day and night: hospitality extends for three days; what goes after that is sadaqah(charity): and it is not allowable that a guest should stay till he makes himself an encumbrance. Abu Dawud said: Malik was asked about the saying of the Prophet: "Provisions for the road what will serve for a day a night." He said: He should honor him, present him some gift, and protect him for a day and night, and hospitality for three days.
أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلْيُكْرِمْ ضَيْفَهُ جَائِزَتُهُ يَوْمُهُ وَلَيْلَتُهُ الضِّيَافَةُ ثَلاَثَةُ أَيَّامٍ وَمَا بَعْدَ ذَلِكَ فَهُوَ صَدَقَةٌ وَلاَ يَحِلُّ لَهُ أَنْ يَثْوِيَ عِنْدَهُ حَتَّى يُحْرِجَهُ