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."

"When people see an oppressor but do not stop him, Allah will soon overwhelm them with a punishment from Him."

"Among the best of Jihad is to speak a word of justice to an oppressive ruler."

"Let not the fear of people prevent any man among you from speaking the truth when he sees it or knows it."

"There will be rulers who tell lies and oppress; whoever believes their lies and assists them in their oppression does not belong to me, and I do not belong to him, and he will not come to the Hawd (Basin). But whoever does not believe their lies and does not assist them in their oppression belongs to me, and I belong to him, and he will come to the Hawd."