We should have more confidence in the sheer obviousness of God's existence
We should have more confidence not just in the Gospel and Spirit, but also in the sheer obviousness of God's existence—and not just God as such, but the God that Scripture presents in his power to create and sustain as well as his eternal existence and nature (and so simplicity, immutability, and so on).
Scripture
The Apostle Paul explains in the first chapter of Romans: "For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made."
What Paul says here is true. Through the clarity of general revelation, we know what can be known about God apart from special revelation. Specifically, we know God’s invisible attributes which include his eternal power and divine nature. The means by which we see them are through God’s created works.
In today’s terms, invisible attributes signify metaphysics—the upper-level description of the things apart from the narrow confines of empiricism. Seeing this through created things means that we can see the ultimate cause (God) in his effects and reason to the logical cause via analogy. So if we see a beautiful flower, we know that its cause had to be as beautiful or more beautiful. The most beautiful thing is God. By analogy from the flower (lower order) to God (higher order), we have come to a true conclusion, albeit a necessarily partial one.
These realities are plain, obvious, and true. We should share the confidence that Paul has in these things.
Obstacles
A number of obstacles prevent people from seeing what Paul describes. First, people choose to suppress the truth due to sin.
Second, what is obvious is different than what is easily grasped. God's eternal power and nature are under no obligation to make perfect sense to you without first meditating on God's beauty and nature.
And third, our will has been so corrupted that when we deliberate, we tend to choose evil over good. So even if we do not intend to love evil over good, we cannot trust our ability to will; we bound to our corrupted capacities. It is the Gospel alone that provides us freedom, so that we might will the good, and eventually erase all possibility of willing evil, which means our wills will reach a state of perfection and not privation as they suffer under now and so guiding us to choose evil.
Confidence
Despite all of this, we can have confidence. God exists plainly since creation shouts his power and nature and reality—saying "God's glory pervades the globe." That's true. Be confident. Witness to the truth. Do not fear it or make excuses for it.
