Sunan Ibn Majah, Book 4, Hadith 7 (In-Book) ⓘ
It was narrated that 'Umar bin Khattab said: The Messenger of Allah said: "No people's deeds ever became evil deeds but they started to adorn their places of worship."
حَدَّثَنَا جُبَارَةُ بْنُ الْمُغَلِّسِ، حَدَّثَنَا عَبْدُ الْكَرِيمِ بْنُ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي إِسْحَاقَ، عَنْ عَمْرِو بْنِ مَيْمُونٍ، عَنْ عُمَرَ بْنِ الْخَطَّابِ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَا سَاءَ عَمَلُ قَوْمٍ قَطُّ إِلاَّ زَخْرَفُوا مَسَاجِدَهُمْ " .
also referenced under: Hadith 741 (Reference) & Volume 1, Book 4, Hadith 741 (DarusSalam)