Sahih Muslim , Book 4, Hadith 1703 (USC-MSA) ⓘ
Ibn 'Umar reported Allah's Apostle 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 " .
also referenced under: Book 6, Hadith 248 (In-Book) & Hadith 777 (Reference)