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Wilayatul Faqih in Islamic Beliefs:
Wilayatul faqih and Imamate are intertwined, because if wilayatul faqih is looked at from the same perspective as imamate is, its theological dimension will show itself, making it a theological subject as is imamate.
Explanation: If we look at imamate as something done by Allah (swt), just like how we look at prophethood and the sending of messengers, and ask ourselves “Has Allah (swt) appointed someone after the prophet (pbuh) who is to be responsible for the guidance of the people?” and “Is it an ‘obligation’ and necessary for Allah (swt) to appoint one as imam (as) after the prophet (pbuh)?”, it will become a theological issue. Now, if we look at wilayatul faqih as a continuation of the guardianship and authority of the imams (as), and ask ourselves the same question regarding the appointment of the faqih as we did regarding the appointment of the imams (as), and look at this issue assuming that it is also something that Allah (swt) has done, like we did concerning the appointment of the imams (as), then it will also be a theological issue. Of course, our Sunni brothers consider this issue to be a fiqhi one, because the majority of the Sunnis only see prophethood as a theological issue and not imamate; to them imamate is a fiqhi issue (making wilayatul faqih also a fiqhi one because as was said, the two are intertwined; whatever imamate is considered, wilayatul faqih is also considered, if the first is a theological issue, the second will also be, and if the first is a fiqhi, it will make the latter also a fiqhi one).
According to what some faqihs and Islamic scholars have explicitly said, the issue of wilayatul faqih itself is accepted by the majority (if not all) of scholars. The difference of opinion only lies in the faqih’s area of jurisdiction and how it is proven through Islamic sources.
Imam Khomeini (rah) would insist that all the reasons that prove the appointment of the infallible imams (as) also prove the concept of wilayatul faqih and the establishment of an Islamic government during the major occultation.
Therefore, the same way a Shia and mu’min individual must believe in the wilayah and authority of the infallible imams (as), he must also accept wilayatul faqih as an authority in continuation of that of the imams during the major occultation, because the concept of the authority of the jurist and faqih in every era is one of the pillars of the Shia twelve imamer belief that has roots in the concept of imamate itself, thus it is upon all to obey the faqih. Those mujtahids who don’t believe in this concept as a result of their expert viewpoints are excused, but it isn't permissible for them to cause division amongst the Muslims. Of course, since Sunnis look at the issue from a fiqhi perspective (in contrast to the Shia who see it as theological), they don’t have to obey the waliyy faqih in subordinate issues, but still must obey him when it comes to social and government-related ones.
So, wilayatul faqih or the authority of the faqih and jurist in governing the Muslim nation, is a concept that might not be accepted by some theoretically, but they have to follow him in practice, and this is something that the mind tells us to do (to follow him), because if we fail to do so, confusion, chaos and anarchism will overtake the Muslim nation.
1- Question 39 (website: 272), Wilayatul Faqih and Marja’iyyah
2- Question 1439 (website: 1445), The Area of Wilayatul Faqih
3- Question 2121 (website: 2262), Management dimensions of Wilatyatul Faqih
 In order to learn the meaning of wilayatul faqih and the absolute wilayatul faqih, see Questions 1439 (website: 1445) and 3105 (website: 3370).
 Ahmad Vaezi, Hukumate Eslami, pg. 142 and 143; Ali Rabbani Golpaygani, Din va Dowlat, pp. 125-128; Abdullah Javadi Amoli, Velayate Faqih, pg. 143.
 Din va Dowlat, pg. 128.
 Ahmad Naraqi, Awa’idul-Ayyam, pg. 186; Mohammad Hasan Najafi, Javahirul-Kalam, vol. 2, pg. 398.
 Imam Khomeini, Al-Bey’, vol. 2, pg. 461-462.
 Ayatullah Khamenei, Ajwibatul-Istifta’at (Answers to religious inquiries), vol. 1, with help from pp. 23-27 (summarized).