For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who [hold down] the truth in unrighteousness: because that which may be known of God is manifest in them; for God manifested it unto them. For the invisible things of him since the creation of the world are clearly seen, being perceived through the things that are made, even his everlasting power and divinity; that they may be without excuse: because that, knowing God, they glorified him not as God, neither gave thanks; but became vain in their reasonings, and their senseless heart was darkened. [Rom 1:18–21]
We shall not attempt to give an exegesis of this most difficult passage. It may suffice to call attention to the following matters. In the first place we observe that Paul says that men do actually in some sense see the truth. We do not do justice to this passage by merely saying that all men or most men believe in a god or believe that God probably exists. Paul says that the revelation of the only existing God is so clearly imprinted upon man himself and upon his environment that no matter how hard he tries he cannot suppress this fact. As psychologically active self-conscious creatures they must see something of the truth. They hold down the truth, to be sure, but it is the truth that they hold down. Nor is it that this truth is objectively placed before them only in nature and in the make-up of man. It is, to be sure, on this that Paul does lay the emphasis. But knowledge is also in man in the sense that his subjective reaction to that which he sees shows some acquaintance with the truth. The invisible things of God are perceived (kathoratai). Knowing God (gnontes ton theon), they have not glorified God. In the second place, it is primarily in this fact that men know and do not live up to what they know that Paul sees the greatest folly. Though they knew God, yet they glorified him not. They hold down the truth that is in them as well as round about them. It is in this immediate connection that Paul speaks of the revelation of God’s wrath. He says that God’s wrath is displayed on men just because they hold down the truth in unrighteousness. It is true that God’s wrath is displayed on whatever form unrighteousness may take, but it is specifically mentioned here that God displays his wrath because men hold down the truth.
– Cornelius Van Til, An Introduction to Systematic Theology p.165-166