Surah Al-Muminoon (23) — Ayah 53

But they divided their affair among themselves into factions [57], each group rejoicing in what they have.

[57]
The Principles of Religion Are Four, but the Sects Are Hundreds:

That is, only a few fundamental matters were included in the original religion. And every prophet continued to present these same principles of religion. But people, by differing in these very principles, created hundreds of sects. For example, take the first principle, monotheism (Tawheed). Satan invented dozens of new forms of polytheism and led people down that path. Some people declared a person, a prophet, or angels to be the children of Allah. The belief in incarnation and avatar was fabricated, and Allah Ta'ala was said to descend into the bodies of certain people. Some said that a certain personality is a (separated) light from the light of Allah. Many beings, besides Allah, were accepted as Knower of the Unseen and Present and Watching. And above all, the human being, who was created superior and nobler than all creation, attached his benefit and harm to stones, trees, cattle, stars, jinns, ghosts, and shrines. And he began to bow his head in submission before them. He began to ask them for the fulfillment of his needs.

How Sects Are Formed and the Self-Righteousness of Every Sect:

The second principle is faith in the Hereafter. Some people outright denied the Day of Judgment and resurrection. And those who accepted it did not understand its requirements. Some said that since we are the descendants of prophets or Sayyids, how can we be punished? Some people invented the belief in intercession, that if we pledge allegiance to a certain person, he will intercede and save us. Some attached this belief to their deities or idols. The Christians fabricated the doctrine of the atonement of Christ, and some priests, even in this world, began to extort money from people and issue them pardons. And some people invented the belief that if one passes under the heavenly gate of a certain saint on the day of his festival, salvation is guaranteed. All such beliefs in cheap salvation are absurd and false. And the Quran has declared those who hold such beliefs to be deniers of the Hereafter, i.e., disbelievers. The third principle was related to eating lawful and pure things, but even in this, people created paths of excess and negligence. Monks, sheikhs, and some Sufis declared lawful things forbidden upon themselves. And others abolished the distinction between lawful and unlawful altogether and tried to prove as lawful such things as usury, which has been declared unlawful in all the divine laws. Many scholars, sheikhs, caretakers of idols, and custodians of shrines and tombs assumed the authority to declare things lawful and unlawful themselves, and such people have been mentioned in the Quran multiple times. The fourth principle was righteous deeds. Probably in this principle, even more sectarianism occurred than in the matter of polytheism. Some fundamental commands of religion were distorted, and innovative beliefs and practices were included, and the real basis of these things was love of fame and wealth, and countless political and innovative sects came into existence. Among these is the belief in personal imitation (taqleed shakhsi), through which imams were given the status of prophets or even considered above them. Thus, by differing from this simple and concise fundamental teaching, people who were in reality one community, kept dividing into hundreds and thousands of sects. And the interesting thing is that every sect considers itself to be on the truth and regards other sects as fuel for Hell. Whereas this fundamental teaching still exists today, and if any person or sect, rising above prejudice, wishes to seek the path of truth, then the path of truth is not something so hidden even today that it cannot be found.