For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, because what may be known of God is manifest in them, for God has shown it to them. For since the creation of the world His invisible attributes are clearly seen, being understood by the things that are made, even His eternal power and Godhead, so that they are without excuse (Rom.1:18-20)

I do not have to prove to you that God exists, because I think you already know it. Your problem is not that you do not know that God exists; your problem is that you despise the God whom you know exists. Your problem is not intellectual; it is moral— you hate God.

Every moment since the dawn of creation God has been manifesting Himself through the things that are made (v. 20). God did not give us a world and just say, “Sit down and begin to think about where that world came from and reason from the cosmos back to God.” We are to do that, but it is more than that. Every second, God is manifesting Himself through the things that are made so that His testimony to His nature is plainly evident.I am frequently asked, “What happens to the poor, innocent native in Africa who has never heard of Jesus?” That poor, innocent native in Africa goes straight to heaven when he dies. He has no need for a Savior. Jesus did not come in the world to save innocent people. There are no innocent natives in Africa or in Australia, South America, Europe, Asia, or anywhere else. People think that those who have not heard of Jesus are surely innocent, but Jesus came into a world already under the indictment of God the Father because it has rejected Him. We must disavow ourselves of the idea that there are innocent people anywhere. People also ask, “Will God send people to hell for rejecting Jesus, of whom they have never heard?” God is not going to punish someone for rejecting somebody he has never heard of, but their destination is hell for the rejection of the One they have heard of. Every human being knows of God and clearly perceives God but rejects that knowledge. For that, every person is exposed to the wrath of God. The only possible way someone can be rescued from that wrath is through the Savior.

Ungodliness and unrighteousness are vast generic terms that cover a multitude of sins, but Paul is not talking about a multitude of sins here. He has in view one particular sin. It is a universal sin, one committed by every human being. It is the sin that most clearly expresses our Adamic nature, our corruption and fallenness in the flesh. Paul does not leave us to guess at the nature of this sin; God is provoked to an orgy of anger against the sin of those who suppress the truth in unrighteousness (v. 18). The single sin that provokes God’s wrath against the whole human race is the sin of suppressing truth. The root of the Greek word translated “suppress” is katacain, which can also be translated as “to hinder,” “to stifle,” “to incarcerate,” “to put in detention,” “to obscure,” or “to repress.” We might think of a gigantic spring or coil that would require all the strength in our body to push down or compress. While we are pushing it down, it is resisting our strength and seeking to spring back up and recoil into its original position. By nature we take the truth of God and press it down. We force it into our subconscious, as it were, to get it out of our mind; yet, despite all the strength we use to suppress it, we simply cannot eradicate it. We cannot get rid of it because it is always and everywhere pushing back up. The specific sin here is the suppression of truth. What truth is being suppressed? Paul tells us: because what may be known of God is manifest in them, for God has shown it to them (v. 19). The truth that every human being suppresses is the truth of God, what God reveals of Himself in nature to the whole human race. This is not the truth of God that we learn through the Bible. We suppress that too, but here Paul is writing of a truth that is known about God apart from the Bible, a knowledge of God that God makes manifest. The Greek word is phoneros, which means “to show plainly.” We use the term phenomenon, which is derived from that Greek word. The Latin text translates it as manifestum. The knowledge God gives of Himself is not obscure. It is not buried with hidden clues that only an intellectual, elite group of people are able to discover after a painful and tedious search of sifting through the evidence. The truth God gives of Himself is manifest. It is clear— so plain that everybody gets it.

The agnostic portrays himself as a less militant form of atheist. The atheist boldly declares that there is no god, but the agnostic says, “I don’t know if there is a God. I’m agnosis; I am without sufficient knowledge to make a firm judgment on this matter.” (Incidentally, the Latin term for agnosis is ignoramus.) Agnostics think they are not as militant as atheists, but they do not realize that their agnosticism exposes them to greater risk for the wrath of God than if they were militant atheists. Not only do they refuse to acknowledge the God who reveals Himself plainly, but they blame God for their situation, saying He has not given them sufficient evidence.

~ R.C. Sproul [Romans - An Expositional Commentary]