“This sacred knowledge of the religion is going to be taken and carried from every preceding generation by a group of the subsequent generation. They will expel from it the alteration made by those going beyond bounds, false claims of the liars and the false interpretations of the ignorant ones” (Bayhaqi).
From every preceding generation, a group will take knowledge and they will purify from it any misrepresentation of the religion. For example, someone may have come with a new claim about religion and corrupted a number of people; after all, ideas are prone to exaggeration. The whole reason that communism came about is because the core need of man was to have economic stability. In Russia, there was a massive gap between those who had and those who did not, and that is why one need among the many needs of humanity—of economic stability—was promoted as the main need of that time. Eventually that particular need became the dominant aspect around which everything else began to revolve and they formed an entire system around it.
Similarly, let us say there is a time when we need to promote politics in Islam, which is just one of its many aspects. If somebody takes that and makes it the entire crux and spirit of Islam, and begins to say that even your salat (prayer) is part of your Islamic politics and it is a type of training in obedience to the leader, and starts to reinterpret all other acts of worship around a political vision, he will corrupt the entire religion. He has taken one aspect of religion, and made it the core of religion. Therefore, Allah sends people to deal with the consequences of such corruption and innovation. They undertake the work of revival.
-Taken from Mufti Dr. Abdur Rahman Yusuf's article on revival of the Deen.
