كتاب الإيمان
1  
The Book of Faith
(19)
Chapter: Encouragement to honor one's neighbor and guest, and the obligation to remain silent unless one has something good to say, and the fact that all of that is part of faith
(19)
باب الْحَثِّ عَلَى إِكْرَامِ الْجَارِ وَالضَّيْفِ وَلُزُومِ الصَّمْتِ إِلاَّ مِنَ الْخَيْرِ وَكَوْنِ ذَلِكَ كُلِّهِ مِنَ الإِيمَانِ
Sahih Muslim 47 b

It is reported on the authority of Abu Huraira that the Messenger of Allah (may peace and blessings be upon him) observed:

He who believes in Allah and the Last Day does not harm is neighbour, and he who believes in Allah and the Last Day shows hospitality to his guest and he who believes in Allah and the Last Day speaks good or remains silent.
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ أَبِي حَصِينٍ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلاَ يُؤْذِي جَارَهُ وَمَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلْيُكْرِمْ ضَيْفَهُ وَمَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلْيَقُلْ خَيْرًا أَوْ لِيَسْكُتْ ‏"‏ ‏.‏
Reference : Sahih Muslim 47b
In-book reference : Book 1, Hadith 81
USC-MSA web (English) reference : Book 1, Hadith 76
  (deprecated numbering scheme)