كتاب اللقطة
31
The Book of Lost Property
(4)
Chapter: It is recommended to spend surplus wealth
(4)
باب الضِّيَافَةِ وَنَحْوِهَا ‏‏
Sahih Muslim 48 b

Abd Shuraib al-Adawi reported:

My eare listened and my eye saw when Allah's Messenger (ﷺ) spoke and said: He who believes In Allah and the eireafter should show respect to the guest even with utmost kindness and courtesy. They said: Messenger of Allah, what is this utmost kindness and courtesy? He replied: It is for a day and a night. Hospitality extends for three days, and what is beyond that is a Sadaqa for him; and he who believes in Allah and the Hereafter should say something good or keep quiet.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا لَيْثٌ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ، عَنْ أَبِي شُرَيْحٍ الْعَدَوِيِّ، أَنَّهُ قَالَ سَمِعَتْ أُذُنَاىَ، وَأَبْصَرَتْ، عَيْنَاىَ حِينَ تَكَلَّمَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلْيُكْرِمْ ضَيْفَهُ جَائِزَتَهُ ‏"‏ ‏.‏ قَالُوا وَمَا جَائِزَتُهُ يَا رَسُولَ اللَّهِ قَالَ ‏"‏ يَوْمُهُ وَلَيْلَتُهُ وَالضِّيَافَةُ ثَلاَثَةُ أَيَّامٍ فَمَا كَانَ وَرَاءَ ذَلِكَ فَهُوَ صَدَقَةٌ عَلَيْهِ - وَقَالَ - مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلْيَقُلْ خَيْرًا أَوْ لِيَصْمُتْ ‏"‏ ‏.‏
Reference : Sahih Muslim 48 b
In-book reference : Book 31, Hadith 15
USC-MSA web (English) reference : Book 18, Hadith 4286
  (deprecated numbering scheme)