Sunan Ibn Majah, Volume 5, Book 37, Hadith 4118 (DarusSalam) ⓘ
It was narrated from ‘Abdullah bin Abi Umamah Al-Harithi that his father said: “The Messenger of Allah said: ‘Simplicity is part of faith.’”
حَدَّثَنَا كَثِيرُ بْنُ عُبَيْدٍ الْحِمْصِيُّ، حَدَّثَنَا أَيُّوبُ بْنُ سُوَيْدٍ، عَنْ أُسَامَةَ بْنِ زَيْدٍ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي أُمَامَةَ الْحَارِثِيِّ، عَنْ أَبِيهِ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " الْبَذَاذَةُ مِنَ الإِيمَانِ " . قَالَ الْبَذَاذَةُ الْقَشَافَةُ يَعْنِي التَّقَشُّفَ .
also referenced under: Hadith 4118 (Reference) & Book 37, Hadith 4257 (In-Book)