"For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; Because that which may be known of God is manifest in them; for God hath shewed [it] unto them. 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:"
The Letter of Paul to the Romans, chapter 1
Basic Catholic theology. And since the Founding Fathers (of the U.S.) had made so many references to natural law in the foundational documents, I had thought it had long been basic Protestant theology. Then again:
"And many things were forgotten, which should not have been forgotten"
J.R.R. Tolkein, in The Lord of the Rings
God knows how many "Catholics" don't learn any theology these days, so I won't pick on any Protestants if this preacher feels it necessary to teach his flock.
Yes, I love that verse. It's like saying, hey, pull your heads out, look at creation and believe.