BALANCE SCALE:
God had given us enough for us to believe with a surety that He exist.
Such argumentation, evidence, or reason (i.e. 5 Arguments for God*, 2nd Law of Thermodynamics, Rossetta Stone, the discovery of ancient city of Jericho, etc), are so compelling that with one could only conclude that God exists [Assuming that we do not have an innate* sense of God's existence (Romans 1:18-32)].
Yet, there isn't enough of such evidence, particularly physical evidence, to truly or fully "Convince" skeptics of His existence. Why? I believe He had done so for our condemnation Here's what I mean:
Imagine a scale with one that is to believe, and the other to disbelieve. What would tip the scale is not ultimately the volume of, or the potency of evidence, but our will.
Will we believe based on the evidence given, or disbelieve because we love our life of sin more than we value truth? Sadly it is often the latter which is why only the few will be saved.
WILLFUL BLINDNESS
The Bible says that all of us knows that God exists internally but at the same time, we're willfully blnded at the same time,
I believe the reason for that is Congnitive Dissonance. It is a mental filtering* of what we can psychologically bear, and what we cannot. The Bible also says that Satan, the "god of this world" blinded the minds of men so they would not believe His Gospel (2 Corinthians 4:3-4).
So for some of us we look at creation with awe and cannot but conclude that there must be a god, and others just see creation as rocks, plants, trees, animals and sky, but nothing more. They can be filled with wonder like anyone but never see the ontological implication.
SOURCES:
* "William Lane Craig: Five Arguments for God" by Andy Naselli The Gospel Coalition
FEBRUARY 4, 2010 | thegospelcoalition.org/article/william-lane-craig-five-arguments-for-god/
* "Cognitive Dissonance" By Saul McLeod, Simple Psychology updated 2018 https://www.simplypsychology.org/cognitive-dissonance.html
