The following is from the draft english translation of the Arabic book مقدمة الدستورأو الأسباب الموجبة له (Introduction to the constitution and the evidences that make it obligatory) published by Hizb ut-Tahrir 1382 Hijri (1963 CE). Please refer to the original Arabic for accurate meanings. Please note some of the adopted opinions of the Hizb have changed since the time the book was published so any of the adopted literature published after this book which contradicts what is mentioned in this book abrogates those specific points
Article 23:The State's apparatus is built upon eight pillars.
The Khalifah .
The Delegated Assistant.
The Executive Assistant.
The Amir of Jihad.
The State Service Departments.
The Ummah Council.
Evidence of this article is derived from the action of the Messenger of Allah (saw).
He (saw) established the apparatus of the State in this shape. He (saw) was the Head of State and he ordered the Muslims to appoint a Head of State when he ordered them to appoint a Khalifah and an Imam after his departure.
As for the Assistants, the Messenger of Allah (saw) chose Abu Bakr and Omar as his Assistants.
Al-Tirmithi extracted a Hadith in which the Messenger of Allah (saw) is reported to have said:
"My two (Wazirs) ministers from among the people of the Earth are Abu Bakr and Omar."
The meaning of the term Wazir, i.e. minister in this Hadith is Assistant, because that is the linguistic meaning of the word, as for the word Wazir for which people refer today, this is a western jargon referring to a specific ruling function; something which the Muslims do not identify with and something which contradicts the Islamic ruling system. This is so because the Assistant whom the Messenger of Allah (saw) referred to as Wazir, i.e. minister, does not specialise in one specific task; he is rather an Assistant to whom the Khalifah delegates with a general mandate to perform all the actions. It would be wrong to confine his duties to a specific task.
As for the Walis, the Messenger of Allah (saw) appointed a number of Walis over the various provinces.
He (saw) appointed Utab Ibnu Usayd as Wali over Makkah in the wake of its conquest; and when Bathan Ibnu Sassan embraced Islam, the Messenger of Allah (saw) appointed him as Wali over Yemen, in addition to many other Walis.
As for the judges, the Messenger of Allah (saw) used to appoint judges to judges between people. He (saw) for instance appointed Ali Ibn Abi Talib as judge over Yemen;
He (saw) appointed Rashid Ibnu Abdullah as Amir over the judiciary and the Mathalim. The Messenger of Allah (saw) appointed him as judge and conferred upon him the competence to investigate the issues of Mathalim.
As for the administrative system, the Messenger of Allah (saw) appointed a host of notaries to manage the various services. They were like Heads of Departments. The Messenger of Allah (saw) for instance appointed Mu'ayqeeb Ibnu Abi Fatima as a notary in charge of the spoils; Huthayfa Ibnul Yaman used to record the assessments of the produce in Hijaz.
He (saw) also appointed others to supervise the other service departments, and in some case, more than one notary for one service department. As for the army, the Messenger of Allah (saw) was the effective Commander in Chief of the armed forces, and he used to personally supervise the army and run its affairs. He (saw) used to in some cases appoint commanders to carry out certain tasks. The Messenger of Allah (saw) for instance appointed Abdullah Ibnu Ja'hsh to head a task force charged with gathering intelligence about Quraysh.
He (saw) also appointed Salma Ibnu Abdil Assad as commander of an expedition of 150 fighters, and he knotted for him the banner of that squadron; this squadron included some of the best heroes from among the Muslims, such as Abu Ubayda Ibnul Jarrah, Saad Ibnu Abi Waqqas and Usay Ibnu Hudhayr.
As for the Ummah Council, the Messenger of Allah (saw) did not have a permanent chamber, but he used to consult the Muslims whenever he deemed fit. He (saw) summoned them on the day of Uhud and consulted them, and he gathered them on the day of Al-Ifk incident and consulted them, and he also gathered them and sought their opinion in several other issues.
However, despite the fact that the Messenger of Allah (saw) used to gather the Muslims and consult them, there were among them a host of specific persons whom he used to summon regularly. These were from among the chiefs of their folks, such as Hamza, Abu Bakr, Jaafar, Omar, Ali, Ibnu Masud, Sulayman, Ammar Huthayfa, Abu Tharr, Al-Muqdad and Bilal. They acted as the Ummah Council of the Messenger of Allah (saw), because he used to regularly and specifically always seek their opinions.
Therefore, it becomes clear that the Messenger of Allah (saw) has established a distinguished apparatus for the State, that operated in a specific manner. He (saw) continued to proceed according to this apparatus until he departed this world. Then his Khulafa' came and proceeded in the same manner, ruling according to this apparatus which the Messenger of Allah (saw) established. They did this before the rest of the Sahaba; hence, it is determined that the apparatus of the Islamic State should be in this manner.
One might say that the Messenger of Allah (saw) has appointed someone to specifically run the financial department, which may be interpreted that finance constitutes a special apparatus and not part of these apparatuses. The answer to this is that although the Messenger of Allah (saw) appointed a specific person to run the finance and made an independent department, he however did not turn it into an apparatus, but rather part of an apparatus. Some of the Walis whom the Messenger of Allah (saw) used to appoint had a general Wilaya that included the rule and the finance, and other Walis had a special Wilaya, that included the rule, and the Messenger of Allah (saw) used to apoint another Wali specifically for finance. The Messenger of Allah (saw) dispatched Amru Ibnu Hazm to Yemen as a Wali and he (saw) made his Wilaya a general one that included the rule and the finance, as stipulated in the letter that he handed to him.
The Messenger of Allah (saw) also appointed Farwa Ibnu Sayl as Wali over the tribes of Murad, Zubayd and Math'haj and he sent with him Khalid Ibnu Sai'd Al-a'as as Amil over the Sadaqa. The Wali in charge of ruling matters used to be known as the Wali of Salat, which is a terminological term, meaning the governing of people's affairs in all matters related to administration, judiciary, politics, warfare, rituals and other matters, except the levy of funds. The Wali in charge of finance used to be known as the Wali of Kharaj, meaning the collection of Zakat, land taxes and similar. The Wali whose Wilaya was general used to be known as the Wali of Salat and Kharaj.
Therefore, finance was never an independent apparatus, but rather part of the Imara functions, i.e. the Wilaya. This could be assigned to other than the Wali in charge of ruling matters and it also could be assigned to him; in any case it does not have a special competent authority within the State, it comes rather under the auspices of the Khalifah. Hence, it is part of an apparatus and not a special apparatus.
Hence, the State's apparatus which the Messenger of Allah (saw) founded in based on seven pillars only.