There are 2 worlds of Christian in the spiritual world: Heaven and Hell.
If you DO NOT do well in this material world, you will be sent to Hell after you leave this world.
I know that you do not believe that God creates this material world from the scratch, and is NOW a king takes care of this world in another world. I did not believe in this either before I am a Christian.
Have you ever thought who defines the truth ? I used to only believe in science.
Science has a hypothesis: Nothing is faster than the light. And the speed of light is the same in all reference systems.
Science must be:
0) Observable
1) Repeatable
2) Predicable.
Science seeks the truth, but who creates truths ?