God forbid we ignore the arguments proposed in the Scripture for His existence. Paul offers the most famous argument in Romans 1.
Here is what it says:
18: For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men who suppress the truth in unrighteousness. 19 because that which is known about God is evident within them; for God made it evident to them. 20 For since the creation of the world His invisible attributes, His eternal power and divine nature have been clearly seen, being understood through what has been made, so that they are without excuse. 21 For even though they knew God, they did not honor Him as God or give thanks, but they became futile in their speculations and their foolish heart was darkened. 22 Professing to be wise they became fools…
Paul argues that the knowledge of God is innate (evident within them).
A denial of God is suppression of the truth
Paul argues that the knowledge of God is not only innate, but observable (evident to them).
Really Paul appeals to two things here. He appeals to knowledge that he says is basic to all humanity. It is a foundational belief. It is as basic as other ideas that we have such as the principle of non-contradiction. We seem to know without any learning or observing, that things cannot be two different things at the same time. “A” cannot be “A” and “not A” at the same time. Small children know this. I am an incurable tease. One of the games I play with children has to do with this idea of contradiction. I will call something green when it is actually red. Their response is generally immediate and strong. Now I know that they were taught that it was red, but they were not taught that it was not green, but they know this innately. They never respond, “oh, it is red and green?” It is knowledge of this sort that we are saying is knowledge of God.
If it is innate, why aren’t all people theists. Paul answers that question as well. Atheism and unbelief are suppressions of the truth. He identifies this as unrighteousness. Now this isn’t only a moral judgment, it is a judgment of justice and truth. This truth is known to all, unbelief is a rejection of what is genuinely and innately true. This suppression Paul also claims leads to futility in thinking (purposelessness, nihilism) and a cloak of darkness. He also picks up on the Old Testament declaration that this rejection of God is foolishness
It is upon this basic belief of the knowledge of God that a naturalistic argument can be made. The evidence that we can perceive and see teaches us about God’s attributes, power and nature.
Paul really appeals to two lines of argumentation here: what is known in philosophy as foundationalism and the teleological argument.