General Jim Mattis, 40 years in the U.S. Marine Corps.

How do you keep improving as a leader to meet the demand of each role in your career.

We all get promoted, you have different roles to play.

How do you stay teachable as a leader?

I think the most important thing here, Joel, is that you have to assume you must keep improving.

If you make that your decision, you must improve,

if you look at every week in the Marine Corps

is your last week of peace and you must be better

at the end of this week as a warfighter,

then you'll push yourself on your three-mile run down to 18 minutes

and you'll accept no excuses. You'll push yourself on your three-mile run down to 18 minutes, and you'll accept

no excuses.

You'll push yourself 21 pull-ups, and you'll accept no excuses.

You'll push yourself to read the Commandant's reading list.

You'll push yourself that when the things are going tough in the field, you keep your spirit

up and you're the man everyone can turn to knowing that you don't give up.

And you just keep improving every day with the assumption that if you're going to lead more Marines in the future,

as you get promoted, they expect you to be the physically toughest, the mentally sharpest, and spiritually, just the most undiminished

person that nothing, not cold, not rain, not enemy situation, not frustrating rules can get

you down.

And you just maintain this body, mind, and spirit improvement at all times.

You stay teachable most by reading books, by reading what other people went through.

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