I want to share a realization that recently came to me. It is a way of establishing control over a society, allowing you to bend them to your will. However in practice this will take generations to really lodge into society, so you probably won't have direct benefit but your heirs will.
Step 1: Beg, borrow, steal or forge a set of spiritual writings
Step 2: Present those writings as the Word of God
Step 3: Present the writings as being the infallible source of truth
Step 4: Appoint a group of people as the official interpreters of Gods Infallible Words as written in those writings
It helps to have an authentic spiritual guru deliver the writings you are going to start with. That's not an absolute requirement. The other steps serve to separate the individuals in the society from their own authentic ability to determine the truth.
The other steps make it so Truth is determined only from the spiritual writings, and that Truth is so difficult to understand that only the select anointed ones can tell what's right or wrong. Hence when someone has a question, they won't be able to answer it for themselves but instead have to turn to the official interpreters of Gods Infallible Words to tell them the truth.
Once the official interpreters of Gods Infallible Words are established with credibility, then can claim literally any idea as being Gods Infallible Truth. Of course this assumes the official interpreters become corrupt, and no longer be serious students of spiritual truth.
In the ideal the priesthood's role is to explore the divine and to have the freedom to devote their lives to authentic spiritual practice. But we can think of dozens of religions throughout history where it began as an authentic spiritual practice, then devolved into corruption and power mongering.
I believe we all have access to divine truth. There are many spiritual teachings which say so, and which say we can look within for the divine truth. They tend to encourage us to explore and experiment for ourselves divine truth. In my experience the confidence this gives is stronger than "faith".