What in the World?

In order to believe in jesus, people have to hear about him. Paul then raises the expected problem, not everybody has heard about jesus. And he gives an unexpected answer, they have heard. You think, what in the world? Where? How? What's going on here? Now the passage that paul quotes from the old testament is psalm 19 four. Their voice goes out through all the eart and their words to the end of the world. The key question though is, how did paul think the heavens communicated the coming of jesus?