Narrated to us by ‘Abd al-Rahman ibn Mahdi, from Zuhayr—meaning ibn Muhammad, from Salih—meaning ibn Kaysan, that ‘Abd Allah ibn Abi Umamah informed him, that Abu Umamah informed him, that the Messenger of Allah, peace and blessings be upon him, said: "Simplicity is part of faith, simplicity is part of faith."
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 24009/58