1b. In Paragraph 2, Edwards compares the sinner first with a fallen rock and later with chaff on a threshing floor. What does he mean by each of these similes?

Fallen rocks and chaffs of wheat are both seen as useless items..... items that are taken for granted and easily discarded. Like the fallen rock or chaff of wheat, humans are easily discarded..... thrown aside, cast away, and without purpose.