Religion is a means of information dissemination. Now religion is the Internet, before that - television, even earlier – newspapers and books, and in those days when only a select few could read, information could be transmitted only by retelling. For information not to be distorted during transmission, there should be one source of information; those who retell information should receive it from one source. For the reliability of the information is not subject to doubts, those who retell should enjoy authority among the listeners, then they can present a subjective opinion as objective, that is, as truth. As a result, listeners do not need to torment their conscience with a choice, the choice has already been made, and it only needs to be accepted as the truth - to believe.
The means of disseminating information are used to control consumers of information, the goals of this control can be any, for example, so as not to kill each other, because then there will be no one to control. It is possible to manage nutrition, if people do not eat properly, they can get sick, and then they will be of little use. People, like other organisms, spend energy on movement, you can control this movement so that it is orderly, not chaotic, or you can direct the energy to something else. All the resources that a person has can be directed in the right direction.
The world is filled with a variety of religious denominations. Any religious denomination is just a popular sect that was able to take root, defeat other sects in a certain group of people, and then become widespread in other groups of people; therefore it can sometimes be supported even at the state level. What a sect is - this is a topic for another article.