I'm a deity. Unfortunately, my powers are sharply limited:
I cannot affect physical world (except #3) at all.
I "control" whether a person's soul, after the body's death, goes to "heaven" or "hell" according to well-defined rules based on how they lived their life.
I can come into the world as a regular mortal (save my knowledge), and try and convince mortals of things.
Now, I'm an ethical deity, and I have a goal that the most souls possible end up in "heaven".
So what I need is a religion that basically adheres to real truth: here's a set of rules, if you follow them, your soul goes to "heaven", otherwise, to "hell".
QUESTION: Given the limitations on my powers, how can I establish such a "religion" among my creatures, ALL of whom happen to be intelligent beings, with well developed skepticism and rational thinking?
Some specific details of the setting that are relevant, especially my power limits:
Created by me (probably by running a Perl script).
However, it has a set of rules I can't violate (for techies out there, I built the system but forgot the root password and lost the key to server cabinet).
Consists of two levels, material and spiritual.
Generally, material sphere tracks our real world (few meaningful changes outlined below). This includes standard science, Universe, a largely Earth like planet with a single intelligent species (unique to the universe, if you don't count myself).
Spiritual sphere consists of souls, heaven and hell (details below).
Spiritual sphere is NOT detectable by the creatures, using any science and technology they can devise, even if I give them full knowledge of how it works.
My creatures are mortal, intelligent (very), and their minds are naturally rational and skeptical. They have reasonably well developed sciences.
Being rational, they don't currently have any superstitions, religion, etc... They acknowledge they lack information on certain topics (e.g. how/why Universe was created); they have some theories; but don't feel the need for established supernatural explanation of it (nobody wants to find out their existence is a result of a Perl script :)
Probably humanoid but not really relevant. They are the only intelligent species in the Universe.
Each of my creatures has a soul.
Souls and spiritual sphere
Each of my creatures has a soul (and only their species does).
Said soul is undetectable by any science or technology they can achieve (even if you offer them advanced knowledge - you don't know how, yourself).
The soul manifests itself as a body in a spiritual world, in some indeterminate way. Details are hazy and unimportant, for most part.
One being gets one unique soul created for them at birth. The soul is connected with the being, but in immaterial way (e.g. it doesn't really exist in physical universe, but the individual and the soul have same ID#.
When their physical body dies, that soul will become the new being, with full mind/consciousness that used to reside in the material body transferred into the soul's spiritual "body"
Souls are immortal
Upon the individual's death, each soul gets placed into two discrete halves of spiritual world: "hell" or "heaven" (before death, the soul has no existence or location, it's in "storage").
Their precise nature is not really relevant, and they generally track with standard Earth Christian idea in a sense of, souls going to hell will suffer majorly for eternity, souls going to heaven will enjoy afterlife for eternity. The precise nature is irrelevant but can be assumed to roughly match the creatures' own normal understanding of suffering or enjoyment.
Souls in afterlife can NOT return to mortal world - no ghosts, supernatural manifestations, working ouja boards and such exist.
CAVEAT: a soul of a child who dies before they reach the age where they can meaningfully and consciously seal their fate by (not)observing the rules is "recycled" into another newborn instead of being judged. This was specifically designed to prevent "well-meaning" pious people from murdering any children "before they sin, so their souls are guaranteed heaven".
I am a deity.
Meaning, I'm immortal, know "everything" (sorta)
I have a set of powers that are sharply defined and limited. I was the one who designed them, so no whining.
I created the creatures (as a consequence of creating the universe). The creatures material side evolved under universe's rules - standard physics, chemistry, biology as exists on Earth.
Their souls were my creation directly.
I have virtually no discretion over placing the souls in heaven/hell - that happens according to well defined rules.
My goal/wish is for as many souls to end up in "heaven" as possible. Like, 100% would be best.
I cannot affect physical world at all (now that it's been created), with minor exceptions listed below.
This means, no miracles. No events that can prove I'm a deity to these people. They can't see, sense, or "science out" me as a deity, or anything I do in my deity form.
Me in the physical world
I can come into the world as a regular mortal, and try and convince mortals of things.
I can take a form and shape of a regular mortal, at birth.
In that form, I am 100% physically indistinguishable from other mortals, aside from knowledge I possess. No special powers/abilities. The mortal form is just as mortal as any of them.
My knowledge of material world is pretty generic - I know how Universe is built, sorta. Don't have detailed knowledge of advanced physics or technology or other science beyond what I could have learned as a mortal of the time. I can't predict physical events any better than the mortal scientist would. I can't teach them something fancy that proves I'm a deity because no mortal could have such insight.
Moreover, that "manifestation" of me into mortal body looks decidedly un-supernatural. I can only manifest as an abandoned newborn, in a place where other abandoned newborns are likely to be found; have to grow up in that mortal body; and don't possess mental abilities or knowledge above that of a mortal till I'm an adult.
Once the body turns legal adult age, I gain knowledge of who I am, 100% detailed knowledge of spiritual world, and my goal of being there (to convince mortals to change their ways so their souls enter Heaven.
Soul judgement rules.
The rules are fairly clear cut. If you fulfill ALL required, and majority (>50%) of "bonus" conditions, you enter heaven.
The trick is that, a typical intelligent, rational mortal would NOT fill the conditions.
A mortal must believe in My existence as a deity and Universe Creator and Soul Judger. It must be a sincere belief, held for a meaningful amount of time (e.g., no deathbed conversions that Catholicism finds just fine. And no stating "Yes, I believe" as a hedge, with the intent of "Well, I don't really believe, but saying I believe doesn't hurt me any if there's no deity, and helps if there is. Win-win.")
A mortal must not try to commit pre-meditated unjustified murder - success of failure are equally punished (me as the deity gets to decide what's justified... and assume I'm fair and wise in deciding).
A mortal must not steal another's legal property, nor rob them of it under threat of duress. Caveatted exception is when this is done in a genuine case where not taking that property threatens one's life (e.g. you are dying of hunger, or you steal a gun to defend yourself against an attacker).
A mortal must not knowingly create a situation that is engineered to force someone else's soul to "hell". E.g., bullying someone intentionally into murdering you would land you in hell even if you lived an otherwise rightful life.
Optional conditions (you should fulfill a majority of such). There's several, but some examples are below. However, the overriding theme is that average non-believer is just as likely to NOT fulfill the conditions, because they are inconvenient, annoying, etc.... But they aren't outlandishly hard to observe the way, say, Orthodox Judaism is.
A mortal must spend 1/10th their income on employment charity (meaning, they don't simply have to give money, but they must purchase someone's labor who is otherwise not employed).
A mortal may not eat anything but once every two weeks (they get to choose which day though), nor have sexual relations twice a week (they get to choose which days).
You cannot eat meat/products of specific animal (equivalent of pig). Obviously caveatted for genuine danger to life/health, as are most laws.
... other such things.
Just to be clear - there's no mortal, subjective, biased priest, judge, or sovereign to decide on whether the rules were "correctly" observed by someone - me, the deity, is the ONLY judge, once someone dies.