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.
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!’…”
“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]
"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"
The following is related by Al-Wahidi in his Asbab al-Nuzul [The Circumstances of Revelation] regarding Surah 38 verses 5 to 12 “When ‘Umar ibn al-Khattab embraced Islam, the Muslims were overjoyed while the Quraysh was devastated. Al-Walid ibn al-Mughirah said to the nobles and chiefs of Quraysh: ‘Go to Abu Talib and say to him: … Continue reading The Political Significance of the Kalimah
“All praise is for Allah, who rescued us from the darkness of ignorance through the illumination of knowledge, and through it He granted us the discernment to avoid falling into erroneous deception. He laid down for us in the sharī‘a of Muhammad a lofty standard and a manifest guide. This was the best of His … Continue reading Imam al-Shatibi*: The Shari‘ah is Allah’s Best Blessing and Gift to Us
The following is from the translated meaning of the Qur’an (4:59): “O Believers, obey Allah and obey the Messenger and those in authority among you; and if you have a dispute concerning any matter, refer it to Allah and the Messenger if you are [in truth] believers in Allah and the Last Day.” [Rendered by … Continue reading Ibn Hajar on Obeying and Disobeying those in Authority
“All pious Muslims well-read in the Hadith (the compiled sayings of the Prophet*) firmly believe in the need to establish an Islamic State headed by a Muslim Caliph. This is mentioned twice in the Holy Quran and it’s central to the Islamic faith. No Muslim scholar would debate an Islamic state and the caliphate.” [Sami … Continue reading Syrian historian: All pious well-read Muslims believe in the need to establish the Caliphate
[Professor Muhammad Yusuf Faruqi, Hamdard Islamicus, Volume XIV No. 1 (Spring 1991)] After the demise of the Holy Prophet (ﷺ), the Companions decided to choose someone capable of organizing and looking after the affairs of the Ummah, establishing the commandments of the Sharī‘ah and continuing the work of da‘wah which was promulgated by the Messenger … Continue reading Early Fuqahā’ on the Significance and Role of the Khilāfah