كتاب صلاة المسافرين وقصرها
6  
The Book of Prayer - Travellers
(29)
Chapter: It is recommended to offer voluntary prayers in one’s house although it is permissible to offer them in the masjid
(29)
باب اسْتِحْبَابِ صَلاَةِ النَّافِلَةِ فِي بَيْتِهِ وَجَوَازِهَا فِي الْمَسْجِدِ ‏‏
Sahih Muslim 777 a

Ibn 'Umar reported Allah's Apostle (ﷺ) as saying:

Observe some of your prayers in your houses and do not make them graves.
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا يَحْيَى، عَنْ عُبَيْدِ اللَّهِ، قَالَ أَخْبَرَنِي نَافِعٌ، عَنِ ابْنِ، عُمَرَ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ اجْعَلُوا مِنْ صَلاَتِكُمْ فِي بُيُوتِكُمْ وَلاَ تَتَّخِذُوهَا قُبُورًا ‏"‏ ‏.‏
Reference : Sahih Muslim 777a
In-book reference : Book 6, Hadith 248
USC-MSA web (English) reference : Book 4, Hadith 1703
  (deprecated numbering scheme)