Pentagon chief Jim Mattis reveals himself in storytelling moments with the troops

"He recalled the words of a Marine sergeant major when Mattis was just two years into his career:

"Every week in the fleet Marine force is your last week of peace," the sergeant major said. "If you don't go into every week thinking like this, you're going to have a sick feeling in the bottom of your stomach when your NCOs (non-commissioned officers) knock on your door and say, 'Get up. Get your gear on. We're leaving.'"

By leaving, Mattis meant departing for war."