Encyclopedia of Prophetic Hadiths

One day, the Messenger of Allah (may Allah's peace and blessings be upon him) gave us an eloquent admonition that caused hearts to become afraid and eyes to shed tears. Someone then said: O Messenger of Allah, this is the admonition of someone who will soon part; so, advise us. He said: "I advise you to fear Allah and to hear and obey, even if an Abyssinian slave. You will see after me great discord. So, hold fast to my Sunnah and the Sunnah of the rightly guided Caliphs. Bite onto it with the molar teeth. Beware of newly invented matters (in religion), for every newly invented matter is misguidance."

"Lo! Soon a Hadīth from me will be conveyed to a man, while he is reclining on his couch, and he says: ‘Between us and you is Allah’s Book. So, whatever we find in it that is lawful, we consider lawful, and whatever we find in it that is unlawful, we consider unlawful.’ Indeed, whatever the Messenger of Allah made unlawful, it is the same as what Allah made unlawful."

"I advise you to fear Allah, and to listen and obey even if a slave is appointed as your leader. Whosoever among you shall live after me will see much discord. So hold fast to my Sunnah and the Sunnah of the Rightly-Guided Caliphs, and cling to them firmly. Beware of new things (in religion) because every religious innovation is a misguidance."