@Ferris Bueller
You say you must
keep believing to be saved. I see in scripture that initial belief gets you saved, but you can end up like this in your belief:
1 Corinthians 15:2
[2] By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have
believed in vain.
And:
James 2:19
...the devils also believe, and tremble.
A person who sins willfully, even in belief, will face condemnation.
Hebrews 10:26-27
For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
So I can’t help but find error in what you’re saying (unless I’m not fully getting where you’re coming from).