What did we receive from the ancient Roman Empire?

Les explains that while much of our architecture and classical philosophy came out of the Greek Empire, our whole system of courts and judges, law, and a republican type of government came out of the ancient Roman Empire. He then uses the imagery of a stone and a threshing floor: all the remains of these ancient empires will suddenly be rolled under the pictured stone, which is Christ at His Second Coming, and He will literally blow it all away. Les compares this to wheat harvest, where wind separates grain from chaff—the chaff blows out the rear, but the grain goes up in the bin. He says these nations and great empires will blow away like the chaff of a threshing floor, and he connects this to Daniel's closing verses where Daniel is told to wait 75 days, a period that will cleanse the planet of everything that has remained.