“It is seen from the first generation that the Sahabah [رضي الله عنهم] rushed to appoint an Imam and pledge allegiance after the death of the Messenger of Allah ﷺ, and they believed that it is an obligation binding upon them and a right that should be fulfilled immediately, and they avoided its postponement which even made them delay preparing the Messenger of Allah ﷺ for burial since they were busy with the appointment of an Imam; all this because they knew that, should there be a moment in which they have no leader that unites them under one opinion and they face a problem, and they differ in the mode of solving it, then their system would be a mess, unity would be nullified and the laws (aḥkām) would cease (to be lived by). It is because of this that they prioritised rushing towards appointing a leader and they did not occupy themselves during this time with anything else other than that. This is decisive (proof) that appointing an Imam is necessary for the preservation of Islam.”
“I say, and tawfīq is from Allah: Be it known that there is consensus on the point that it is the duty of the Muslims to appoint an Imām according to the law. With regard to the words of the versifier :
‘It is an obligation to appoint a just Imām. Know that this is by divine precept, not the judgement of human reasoning.’
[Commenting on this] ‘Abd al-Salām ibn Ibrāhīm al-Laqqānī said in his Itḥāf :
‘That is, to appoint and install an Imām. This law is addressed to the whole community (umma) as from the death of the Prophet (عليه الصلاة و السلام) until the Day of Resurrection; but when the influential men (ahl al-ḥall wa al-‘aqd) perform this task, it suffices for all, no matter whether it be in times of civil strife or otherwise. This is according to the Sunnis, and, when [the term] Imamate is used unrestrictedly, it means the Caliphate, which is an overall leadership embracing all religious and temporal affairs – [undertaken] on behalf of the Prophet ﷺ.’
Expounding the meaning of ‘by divine precept’ Al-Laqqāni said:
‘It means that the obligation of appointing an Imām over the community (umma) is based on divine law, according to the Sunnis, // for a number of reasons, the chief of which is the ijmā‘ of the Companions (رضي الله عنهم) who so emphasised it that they considered it the most important of duties and were distracted by it from burying the Prophet ﷺ. A similar [situation has occurred] following the death of every Imām up to the present day. However, their disagreement on who is suitable for the office of Caliph does not detract from their agreement on the obligation of appointing one. Thus none of them said that there was no need for an Imām.’
‘According to the Consensus of the Companions (رضي الله عنهم) after the death of the Prophet ﷺ, men should appoint an Imām who will look after their interests. They gave this precedence over all other obligations and people have been abiding by this over the ages. Even if the appointed Imām is not the most suitable, nevertheless the mere act of appointing him is sufficient to discharge the [religious] obligation.’ ”
*Shaykh ‘Uthmān Dan Fodio was born in 1168 AH (1754 CE). He is well known as ‘Dan Fodio’ which literally meant ‘son of the scholar’, as his father was already a well known and established scholar in Hausaland.
For the next thirty years Shakyh ‘Uthmān, along with his family, relatives, fellow scholars and students, committed themselves to da‘wah (calling to islam) and teaching tours throughout Hausa land (West Africa): calling people to establish Islam in their hearts and homes; adhere to the Qur’an, Sunnah and Ijmā‘ (or consensus) of the Sunni scholars; forsake innovation; show compassion towards all Muslims; and to end all forms of political and economic oppression.
When the rulers became fearful and envious of Shaykh ‘Uthmān’s large and loyal following of believers, they began persecuting the Muslims severely.
This led to their being blessed by Allah to perform hijra (emigration) and ultimately to their successful military struggle against the Hausa kings.
Their blessed struggle established an Islamic Sultanate in 1807 CE that became one of the most righteous, just and equitable societies this world has ever known.
 i.e. Shaykh Ibrāhīm al-Laqqānī (d. 1041 H), Jawharat al-Tawḥīd
 Shaykh ‘Abd al-Salām ibn Ibrāhīm al-Laqqānī (d. 1078 H), Itḥāf al-Murīd Sharḥ Jawharat al-Tawḥīd
[Shaykh ‘Uthmān Dan Fodio, بيان وجوب الهجرة على العباد وبيان وجوب نصب الإمام وإقامة الجهاد (Bayān Wujūb al-Hijrah ‘ala al-‘Ibād wa Bayān Wujūb Nasb al-Imām wa Iqāmat al-Jihād), English translation by Fathi Hasan El Masri, Khartoum: Oxford: Khartoum University Press; Oxford University Press, 1978, p. 61]
“It [the Caliphate] is the general authority to undertake the establishment of Religion through the revival of religious sciences, the establishment of the pillars of Islam, the organisation of jihād and its related functions of maintenance of armies, financing the soldiers, and allocation of their rightful portions from the spoils of war, administration of justice, enforcement of ḥudūd, elimination of injustice, and enjoining good and forbidding evil, to be exercised on behalf of the Prophet ﷺ.”
[Shāh Walī Allāh, Izālat al-Khafā’ ‘an Khilāfat al-Khulafā’, Volume 1, p. 13, translated in The Socio-Political Thought of Shāh Walī Allāh, Professor Muhammad al-Ghazali, Adam Publishers, New Delhi, 2004, p. 86 ]