For example, it depends on the idea that this world is real, that you do real things in this world, and that if you do the "wrong" real things then that's a sin.
This basis alone is enough for all of the rest of it to spring forth consistently.
For example, if this world is real and sin is real, then you will start trying to identify what is a sin and what isn't. You'll separate out "good and bad". This immediately produces the notion of good and evil. Some things are considered not sins so they are good, and other things are considered sins so they are evil.
Just the mere of act of existing in a dualistic right/wrong world where real stuff happens and some of is it not right, automatically implies that evil exists. Therefore the doctrine now becomes that you should choose only the good stuff and reject the bad stuff.
This actually isn't really just a Christian perspective. It's really the belief of the EGO, and anyone who has a persona and shadow is participating in the battle of good vs evil. If you believe that some aspects of this world are good and some are not, or that some behaviors are good and some are not, you are believing in a separation between good and evil. It means the good stuff is being spiritualized, is being made special, is given extra value, and is seen as acceptable. The bad stuff is seen as unspiritual, valueless, and unacceptable.
So it's not just Christianity that believes in this dynamic. Anyone with an ego believes in this dynamic, even members of other religions if they believe this world is real and that some of the things in it are more spiritual than others.
This goes on to imply that in order to be spiritual, you must only do the good acceptable things, you must keep your behavior in-line, and you must not "sin". If you do sinful things, you will be guilty of sin and be justified in being punished. It would then only seem "right" to punish the sin and condemn the sinner.
This leads to the idea of God, or the interpretation of God, as someone who judges whether you've been sinful or not, and how he then decides based on that whether you are worthy of heaven/love, or whether you need to be punished in hell. So automatically it creates the belief in heaven and hell as the extremes of sin vs not sin.
Anyone who believes that sins are real, Christian or otherwise, actually does believe in heaven vs hell, and good vs evil. They must, because believing in real sin automatically implies these things. Its a package deal.
So if now God is only going to approve of you if you are "good" and do not do the things which are considered sins, and if God's disapproval is going to land you in hell and punishment, it gives you a pretty good motivation to be "good". So then you focus on that, believing that the more good you become the less evil you become. Makes sense right?
This also then implies that if you DO sin, then you need some kind of special pardon if you're going to be seen as acceptable. Therefore you will need to be forgiven by God or Jesus, and if they decide not to forgive you but to condemn you, then you're on your way to hell. This produces such a huge amount of fear relating to whether you are going to be acceptable or not, whether you can be forgiven, and even the possibility of going to a "real hell" is already a nightmare.
To believe that sin is real automatically leads to believing that hell is real. If sin is evil then obviously sinning produces evil and, you know, there's a "place" where evil then seems to exist, and we call that hell. This belief in real sin produces therefore the belief in "real hell", and just believing that hell is real, alone, is enough to frighten the pants off you. It is not so much that the church itself attempts to use this idea to scare you into conformity and control, although that might've happened to some degree.
The ego doesn't need the church to accomplish this. Anyone who believes sin is real will automatically haunt themselves with this belief that a "real evil" could not only attack and threaten and tempt them, but that they themselves could therefore be vulnerable or susceptible to becoming part of that evil, and wind up in hell, suffering and being damned from love forever. Nasty business. All it takes is an ego.
Also then if God is in a position of having to judge between sinners and the innocent, that now turns God into a judger and and a conditional lover. He will only love IF you behave yourself, and if you don't, He will be the one to send you to hell. The amount of fear produced by reacting to this notion, alone, is horrifying, not to mention that it implies that God is fickle and incapable of unconditional love, and so cannot be trusted.
The idea that you might not be accepted or loved, is deeply upsetting. IF God were like this, which he would HAVE to be if sin and evil are real, you're going to be clinging to the edge of your seat until "judgement day" hoping that you've got some chance in hell of not being sent into the pit.
Again this is not just a Christian viewpoint, to be fair, it is the viewpoint that underlies EVERYONE who has an ego. Almost everyone on the planet has bought into this entire thought system as a complete package. Believe in even just one PART of it and you must automatically believe in the rest of it, because it all ties together perfectly logically and leads to all of the other implications.
If you are a A Course in Miracles student, or a Hindu, or a Buddhist or whatever, or an Atheist, if you believe the physical world is real and that it contains good and bad, YOU DO BELIEVE IN HELL, SIN, A JUDGEMENTAL GOD, SACRIFICE, THREAT OF DAMNATION, SUFFERING AND DEATH. If you think you don't, and you have an ego, you're in denial.
In order for you NOT to believe any of this thought system, or any of the parts of it, there MUST be a decision on your part not to believe at least one PART of it. For example, if you were to believe that sin is not real, this AUTOMATICALLY IMPLIES that the entire rest of the ego thought system, the entire rest of "christianity", is false.
If sin is not real, there is no good and bad or right and wrong, things appearing to happen are just illusions, God is unconditionally loving and nonjudgmental, there is no real evil, there in no hell, and you are One with God in Heaven forever. And that's all an automatic logical conclusion that is part of the package deal you get when you believe that sin is not real.
You could also say, I do not believe the world is real. That too will put a pin in the entire ego thought system based on good vs evil, and will completely undermine every part of it. If the world is not real and God did not create it then there is also no real evil and no sin or death and no hell to speak of, and nothing that seems to happen here can prove that you are sinful or guilty, therefore you are already eternally forgiven.
So it's really down to the thought system, and its logical consistency. The ego's thought system is responsible for creating Christianity, it is responsible for creating all political parties, it is responsible for creating all wars and conflicts, it is responsible for creating all belief in sin and evil and hell, it is responsible for all suffering, all sickness, and all death, regardless of what form the belief system seems to take or how it's structured or what side you're on.
What A Course in Miracles is trying to teach is that the entire ego thought system and ALL of its contents, IS NOT TRUE. And that means, since truth=reality, it is not REAL. This doesn't throw Jesus Christ out the window, in fact, because Jesus wrote ACIM and He is teaching us through it the "correction" of not only Christianity's interpretation of reality, but also the entire ego's, which includes far more. It's trying to show us the way out, the truth and the light, and the correct interpretation of what is happening here.
It's teaching us that the world is not real, sin is not real, sickness is not real, death is not real, it's all an ego illusion. God is unconditionally loving, forgiveness is universal and permanent, and only love is real.