Robert Heinlein said as much, though in far fewer words that: "An armed society is a polite society." The Munchkin Wrangler has elaborated nicely on Heinlein with an essay that everybody should read.
In a truly moral and civilized society, people exclusively interact through persuasion. Force has no place as a valid method of social interaction, and the only thing that removes force from the menu is the personal firearm, as paradoxical as it may sound to some.
When I carry a gun, you cannot deal with me by force. You have to use reason and try to persuade me, because I have a way to negate your threat or employment of force. The gun is the only personal weapon that puts a 100-pound woman on equal footing with a 220-pound mugger, a 75-year old retiree on equal footing with a 19-year old gangbanger, and a single gay guy on equal footing with a carload of drunk guys with baseball bats. The gun removes the disparity in physical strength, size, or numbers between a potential attacker and a defender.
As the legendary Arizona lawman had engraved on his Colt .45,
"Be afraid of no man,
No matter what size.
When trouble threatens, call on me,
For I shall equalize."
Celebrate National Ammo Day, November 19th.