What the treatment is, and why it is not in this course
For this presentation the treatment with the best evidence is exposure and response prevention. In plain words, it means working out with a trained person how to change what you do when the thought arrives, in steps you agree together, so that the loop stops being fed.
It works, and it works for religious content specifically. Good clinicians do this alongside a scholar where the person wants that, so that what is genuinely required in the religion is never mistaken for a symptom and nothing gets treated that should have been left alone.
We are not going to walk you through it, and you should not assemble it from an article. Done alone it commonly goes wrong, in one of two directions. People avoid inside their own exercise without noticing, so nothing changes and they conclude they are beyond help. Or they overshoot into distress they cannot manage and stop everything.
Naming a treatment raises the chance somebody gets it. Instructing it from a website does not.