John Calvin Commentary Romans 1:20

"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:" — Romans 1:20 (ASV)

Since his invisible things, etc. God is in Himself invisible; but as His majesty shines forth in His works and in His creatures everywhere, people ought to acknowledge Him in these, for they clearly reveal their Maker. For this reason, the Apostle in his Epistle to the Hebrews says that this world is a mirror, or the representation of invisible things.

He does not mention all the particulars that may be thought to belong to God; but He states that we can arrive at the knowledge of His eternal power and divinity. For He who is the framer of all things must necessarily be without beginning and from Himself. When we arrive at this point, the divinity becomes known to us, which cannot exist except accompanied by all the attributes of God, since they are all included under that idea.

So that they are inexcusable. It therefore clearly appears what the consequence is of having this evidence—that people cannot allege anything before God’s tribunal to show that they are not justly condemned. Yet let this difference be remembered: the manifestation of God, by which He makes His glory known in His creation, is, with regard to the light itself, sufficiently clear; but on account of our blindness, it is not found to be sufficient.

However, we are not so blind that we can plead our ignorance as an excuse for our perverseness. We conceive that there is a Deity; and then we conclude that whoever He may be, He ought to be worshipped. But our reason fails here, because it cannot ascertain who or what sort of being God is.

Therefore, the Apostle in Hebrews 11:3 ascribes to faith the light by which a person can gain real knowledge from the work of creation, and not without reason; for we are prevented by our blindness, so that we do not reach the end in view. Yet we see so far that we cannot pretend any excuse.

Both these things are strikingly set forth by Paul in Acts 14:16-17, when he says that the Lord in past times left the nations in their ignorance, and yet He did not leave them without witness (amarturon), since He gave them rain and fertility from heaven. But this knowledge of God, which avails only to take away excuse, differs greatly from that which brings salvation, which Christ mentions in John 17:3, and in which we are to glory, as Jeremiah teaches us, Jeremiah 9:24.