It must be known that this aspect of Islam, i.e. the enjoining of what is right and forbidding of what is wrong, has largely been neglected for a very long time and very few aspects of it remain. Yet it is very important, indeed it is the principle that ensures society remains on the right course. When evil spreads, punishment is inflicted on the good and the bad alike. Unless people stop injustice, Allah may well extend his punishment to all of them. He says: ‘Let those who would go against His bidding beware, lest some affliction or painful suffering befall them’ (24:63). Its benefit is great indeed, particularly because it has been largely neglected, and a person who seeks success in the life to come and hopes to earn Allah’s pleasure should be keen to undertake this duty.
From Muhammad, Messenger of Allah, to Jaifar and 'Abd, sons of al-Julanda, and may peace be upon those who follow Allah's guidance. To proceed, I invite you both to Islam; accept Islam and you will attain salvation, for I am Allah's Messenger to all mankind so that I may warn those who are alive and establish (Allah's) word over the unbelievers. If you declare your Islam I will appoint you both as governors [of your lands], but if you refuse then (know that) your dominion is only fleeting, and my horsemen will dismount in your courtyard, and my Prophethood will prevail over your dominion.
‘How dare you slumber in the shade of complacent safety leading lives as frivolous as garden flowers, while your brothers in Syria have no dwelling place save the saddles of camels and the bellies of vultures? Blood has been spilled! Beautiful young girls have been shamed, and must now hide their sweet faces in their hands! Shall the valorous Arabs resign themselves to insult, and the valiant Persians accept dishonour?’
“Another characteristic expected of the scholar is that he keeps away from the rulers and, as long as he can help it, not to come near them at all, and rather avoid their company despite any efforts on their part to seek him out, because the world is attractive and inviting while the power to dispense with its riches is in their hands. To associate with them, therefore, would necessarily involve the scholar in seeking their approval and winning their hearts, although they are unjust and unrighteous. It is, then, the duty of every religious man to censor them by exposing their tyranny and decrying their practices. For he who frequents their palaces will either seek their favour and consequently forget the blessings which Allah has bestowed upon him, or hold his peace and allow their misdeeds to go uncensored, thereby courting their favour.”
I later asked [‘Izz al-Din Ibn ‘Abd al-Salam] when he had returned from the Sultan and had publically done this good: ‘My master how are you?’ he replied, My son, I saw [the Sultan] in that grand state and wanted to humiliate him in case he puffed himself up with pride.’ I then asked him: ‘My master did you fear him?’ He replied, ‘My son, I swear by Allah, when I recalled Allah’s Majesty in my heart, the Sultan became like a kitten in front of me!’…”
"Let it be noted of the first generation, as to how the Companions (رضي الله عنهم) hastened after the death of the Messenger of Allah ﷺ to appoint the Imam and contract the pledge of allegiance, and how they believed that it was a conclusive obligation (farḍ), a right and mandated (wājib) with immediacy and urgency, as well as how they left the preparation of the Messenger of Allah ﷺ (for burial) through being busy with it (appointing the Imam)."
“Al-Qurtubi, as well as other scholars, said that this Āyah (2:30) proves the obligation of appointing a Khalīfah to pass judgements on matters of dispute between people, to aid the oppressed against the oppressor, to implement the Islamic penal code and to forbid evil. There are many tasks that can only be fulfilled by appointing the Imam, and what is necessary in performing an obligation, is an obligation itself.” [Tafsir Ibn Kathir, Vol. 1 p. 185]
In his book The Mercy in the Difference of the Four Sunni Schools of Islamic Law, Qāḍī Ṣafadī* writes: The Imams [Abū Ḥanīfah, Al-Shāfi‘ī, Mālik and Aḥmad bin Ḥanbal] agree that having a ruler [caliph] is an obligation and that the Muslims must have a ruler to establish the practices of the dīn and to … Continue reading The Four Sunni Imams Agree that the Muslims Must Have a Caliph
Ibn ‘Adi has narrated from Abu Hurayrah (ra) that the Messenger of Allah ﷺ said, ‘In Hell, there is a valley from which the Fire seeks refuge seventy times a day. Allah (swt) has prepared it for the jurists who act to be admired by people. And the most hated of people to Allah (swt) is the scholar of the ruler.’
"and that would be part of the dīn of Allah which is obliged for him, just as every responsible person knows from the dīn of Allah what is obliged for him regarding the five prayers, fasting Ramadan, ḥajj and the like"