However...
However, if fundamentals of religion imply, from an Islamic perspective, those ones that are of belief and faith, to the exclusion of practical acts of worship, there remain other matters that merit believing in, such as the angels: “The Messenger believed in what had been revealed to him from his Lord, as do the men of faith, each one (of them) believed in Allah, His angels, His books, and His Messengers..” (2/285) Again, what sets the Divine Attribute of Justice apart from the other Attributes, such as Omniscience, Omnipotence, Life, Hearing, etc.
to warrant a place among other articles of faith? If believing in God’s Attributes is fundamental, it then follows that one has to believe in all the Attributes. If it is not the case, no other Attribute should be left out. The crux of the matter is that the reasons for choosing these fundamentals are that they are regarded as fundamentals worthy of advocating in the view of Islam. On the other hand, they represent one of the distinct features of the [Shia] School of Thought.
However, Islam has validated the fundamentals of monotheism, justice, and prophethood, and thus upholding them is considered one of Islam’s goals. As for the fundamental of justice, it is distinctively Shia. That is, although Justice is not different from the other Attributes, nor is it one of the objectives of the faith, yet it represents the Shia’s special vision of Islam.
With Shia, two features characterize Justice, in that it falls within the domain of the articles of the faith and clearly defines the boundaries of their distinctive School of Thought. Going back to the belief in the angels, which is predetermined in the Holy Qur’an, why did it not feature among the five fundamentals?
The answer to this question is that those five fundamentals of belief fall within the objectives of Islam, in that the Prophet (s.a.w.) called on people to embrace them and that his noble mission was contingent on this belief. As for believing in the angels and all necessities of religion, such as prayer and fast, they are not among the goals of the Prophetic Message. Nevertheless, they go hand in hand with it.
In other words, this belief is deemed a prerequisite to believing in prophethood, and not among its aims. Should we consider the fundamental of Imamate from social and political perspectives, i.e. power and leadership, it is like Justice, i.e. it does not come under the umbrella of matters of faith.