There is a way that seems right to a man, but its end is the way to death. PROVERBS 16:25 (ESV)
It’s not uncommon to hear people say, “What you believe about God is up to you, it doesn’t really matter.” Perhaps that is your belief. It sounds nice, but what if that’s not true?
What if somebody chose to believe that gravity was not real for them? What if they then chose to walk off the edge of a five-story building? Would their belief regarding gravity, regardless of how sincerely they believed it, have any effect on reality? Is the law of gravity subject to personal belief? Of course not. We are subject to the law of gravity regardless of our personal beliefs. This is true of both physical and spiritual reality.
As individuals with moral agency, we are free to believe or not believe in God. However, we are not free from the consequences of that choice. If God is not real, than believing in him is inconsequential. If God is real, ignoring or denying him will ultimately end as tragically as ignoring or denying the reality of gravity. What an individual believes about God is the most important thing about them.