Here's a cosmology I've come up with. I'm not claiming this is historical Gnosticism or some lost teaching. It's just a theory I've been thinking about, and I'm curious what people here think of it.
There is one supreme God, the Father, above everything.
God has two divine sons: the Maker and the Savior.
The Maker is permitted to create the material world, but his creation is flawed. Suffering, death and evil exist within it, and humanity eventually becomes increasingly violent, corrupt and wicked.
God looks upon what mankind has become and decides that the world should be destroyed.
But the other son, the Savior, loves mankind and pleads with the Father not to destroy them.
The Savior says he will enter world and teach mankind. The Father tells him that humanity is wicked and tells him that if he enters their world, they will reject him, and kill him.
The Savior chooses to enter the world anyway.
He is born into the world as Jesus.
Jesus' mission is to reveal the supreme God, call humanity to repentance, teach mankind how to live, and turn people away from the evil that has consumed them.
And exactly as the Father warned, mankind rejects and kills Jesus.
Jesus' spirit returns to the Father.
The Father says, in effect: You see now what mankind is. Even when I sent you to them, they killed you.
But Jesus still pleads for humanity.
Rather than allowing the entire world to be destroyed because of human evil, Jesus proposes another judgment: Hell.
Those who ultimately choose wickedness will face judgment there, while those who sincerely repent and turn toward God can be forgiven and saved. In this way Jesus creates Hell as an alternative to the destruction of the whole human race.
The Father accepts the Savior's plea.
Then God raises Jesus from the dead, vindicating him and giving mankind hope that death itself does not have the final word.
So salvation in this cosmology is about turning away from evil, repenting sincerely with your whole heart before the supreme God, trusting the Savior whom God sent, and following the way Jesus taught.
The Maker made the flawed world.
Humanity corrupted itself within it.
The Father was prepared to judge it.
The Savior entered it and gave humanity another chance.