These verses declare that knowledge concerning God is available to all, as it is seen in the created world, accessible to the entire human race. [The first step of wisdom is to listen to the worst that God says about us. We were born into this lost race.]
19] Because that which may be known of God is manifest in them; for God hath shewed it unto them.
“Manifest” = visible, clear.
“Shewed it unto them” = the verb related to the noun.
20] For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:
Paul may have intended a play on words between the noun translated “invisible things,” atoj aoratos, and the verb translated “clearly seen,” kaqora/tai, kathoratai, because they share a common Greek root. Both the verb “clearly seen” and the participle “being understood” are in the present tense, which emphasizes the continuous nature of the action. How can something that is invisible testify to something that is clearly seen? DNA is a great example: it is a 3-out-of-4 error correcting digital code! Complex systems such as our bodies have to have subsystems that all communicate on an intimate level. This is evidence of skillful design and implementation. Everywhere in the universe is evidence of design—men are without excuse.
“Things that are made” = poi, hma poiema, workmanship, poem. The Creation is God’s great epic poem (Cf. Eph 2:10).
Paul connects observing Creation, which all people see, as revealing God’s unseen character—the all-powerful Deity. Cf. Old Testament parallel to these verses is Psalm 19:1-6. (A cosmic code which nobody can erase!) Also, Psalm 8:1-4 and Psalm 148 (see below):
Psalm 148 (as paraphrased by Werner Gitt)
Praise the Lord, all you galaxies, appearing like mere dust motes on photographic plates. Praise the Lord, Sirius and your companions Arcturus, Aldebaran, and Antares. Praise the Lord, all you meteorites, all you comets and planets in your elliptical orbits.
Praise the Lord, atmosphere and stratosphere, X-rays, and radio waves. Praise the Lord, all you atoms and molecules, protons and electrons, protozoa and radioaria.
Praise the Lord, all you birds and dragonflies, rushing by in the sky. Praise the Lord, all you microscopic hexagonal snow crystals; all you lustrous blue prisms of copper sulphate. Praise the Lord, all you phosphorescent algae, anurida maritima and ligia exotica, floating like sparkling diamonds on the surf.
Praise the Lord, topic of Cancer, Arctic circle; all you storms sweeping across the Atlantic Ocean and along the Humboldt current.
Praise the Lord, dark forests of the Amazon, all your tropical islands with your volcanoes, and you, O moon, shining on the swaying palms surrounding the lagoon.
Praise the Lord, all you public servants, all you students, all you young maidens. Let them praise the name of the Lord, for His name alone is exalted; His splendor is above the earth and the heavens. He has raised the fortunes of His people and taken Israel to His heart. Praise the Lord!
Paul’s conclusion to this description of natural revelation is important—all men are without excuse. The witness to God in nature is so clear and so constant that ignoring it is indefensible. Their condemnation is based not on their rejecting Christ of whom they have not heard, but on their sinning against the light they do have (Cf. Pharaoh, Ex 10:16; Philistines, 1 Sam 4:7,8; 5:7, 8, 11; King of Nineveh, Jonah 3:7-9).