Roots of Religion (Usūl al-Dīn)

First we will discuss about the Roots of the Religion, as the root is what is responsible for strength, life and sustenance  of any belief:

Islam's fundamental concept is a rigorous monotheism, called tawhīd. Allah, later will be referred as Allah, is described in chapter 112 of the Qur'an as:"Say: He is Allah, the One and Only; Allah, the Eternal, Absolute; He begetteth not, nor is He begotten; And there is none like unto Him."

1.       Shia faith starts with Tawhid , as the first of the Usūl al-Dīn of the Shia Aqeedah.

Tawhid doctrine of Oneness Allah. It holds Allah is one (wāḥid) and unique (Ahad).There are three categories of Tawhid:

1.       Tawhid Ar-Rububiyyah: It pertains to Allah,and His lordship.Rububiyyah is from rabb. The Islamic definition of rabb; Allah is the one who creates, sustains, and owns the entire creation.

2.       Tawhid al Asma was Sifat: Tawhid al Asma was Sifat is the understanding that Allah is named or qualified only by that which has been revealed in the Qu'ran and the Sunnah and that ONLY those names and qualifications can be used and be testified against the chapter 112 of the Qur'an

3.       Tawhid al-Uluhiya: Tawhid al-Uluhiya is the understanding that none has the right to be deified and worshipped except Allah.

2.       The second of the five Usūl al-Dīn  is Adalah: means justice and denotes The Justice of Allah. The Shias believe that there is intrinsic good or evil in things, and that Allah commands them to do the good things and shun the evil. They believe that Allah acts according to a purpose or design, and human reason cannot comprehend this design or purpose in its entirety (though man must always strive to understand as much as he can).

3.       Nabuwwah is the third principle of the Usūl al-Dīn : Nubuwwah means "Prophethood" and denotes that Allah  has appointed perfect Prophets and Messengers to teach mankind the Allah’s religion. Muslims regard Adem (Adam) as the first prophet and Muhammad as the last prophet. The Qur'an identifies 25 prophets by name, starting with Adam and ending with Muhammad, but only 14 of them were messengers of Allah. The Qur'an, like the quoted passage from the New Testament, may rank a messenger higher than a prophet. For example, whenever both titles appear together, "messenger" comes first. Crucially, a messenger delivers a new religious law (Sharia) revealed by Allah, whereas a prophet continues an old one. Islam considers five Prophet of supreme reverence viz:

1.       Nuh

2.       Ibrahim

3.       Musa

4.       Isa

5.       Muhammad

We have made some of these Messenger (Rasul) to excel the others among them are they to whom Allah spoke, and some of them He exalted by (many degrees of) rank... [2.253]

4.       Imāmah means "leadership" and it is a part of the Shi'a theology. The Twelve Imams are the spiritual and political successors to Muhammad, the Prophet of Islam, in the Twelver or Ithna Ashariya branch of Shia Islam. According to the theology of Twelvers, the successor of Muhammad is an infallible human individual who not only rules over the community with justice, but also is able to keep and interpret the Divine Law and its esoteric meaning. The Prophet and Imams' words and deeds are a guide and model for the community to follow; as a result, they must be free from error and sin, and must be chosen by divine decree, or nass, through the Prophet.

According to Twelvers, there is always an Imam of the Age, who is the divinely appointed authority on all matters of faith and law in the Muslim community. Ali was the first Imam of this line, and in the Twelvers' view, the rightful successor to the Prophet of Islam, followed by male descendants of Muhammad through his daughter Fatimah Zahra. Each Imam was the son of the previous Imam, with the exception of Husayn ibn Ali, who was the brother of Hasan ibn Ali. The twelfth and final Imam is Muhammad al-Mahdi, who is believed by the Twelvers to be currently alive, and in occultation.

5.       Yawm al-Qiyāmah "the Day of Resurrection" or Yawm ad-Din "the Day of Judgment" is believed to be Allah's final assessment of humanity. al-Qiyama is also the name of the 75th Sura of the Qur'an.