Creative Speculation

It permitted a farmer to make more food than was needed to feed one family. This excess created commerce, one can exchange another good or service for food, creating specialists. This permitted the formation of villages, then towns, then cities, and onward to nations.

There had to be leaders, soldiers, administrators, blacksmiths, weaver's, shopkeepers, etc... that needed a common location and protection. Because one farmer could produce food for many people, there had to be a way to dispose of the excess. Things went onward from there, essentially necessitating civilization.

Not my own, I can't remember where I saw it originally.