Leadership Troll Attack!

This one might be a tough one...

One of the most intriguing memes on the internet is the "Trollquote" which involves:

• A clearly recognizable person or character
• A clearly recognizable quote or statement
• A clearly recognizable name that the quote is attributed for

As a ds106 assignment that Darth Ba'al submitted, tells us to:

"The assignment is to take a photo, a quote from a different character than the one in the picture, and a name from a third character different from the other two, place the quote in the picture, and "sign" it with the third person's name. The three characters are to be from three different, but similar in genre, series."

As I kept on seeing Troll quotes with Capt. Picard all over the internet, I kept on associating his leadership character with others. He is my favorite Star Trek captain, and he reminds me a lot of my First Sergeant in the United States Marine Corps, First Sgt. Carson.

This guy was a real Clint Eastwood, come to life! He was a bad ass in every way, but most importantly, a fatherly role model for "Suicide Charley," C. Company of 1st Battalion 7th Marines. He motivated us through every misery during training and in combat. He had some damn motivational speeches, as though we were in a movie. Imagine watching a bunch of warriors ready for war after one of his speeches.

Anyways, he always used to say "Don't think you are, know you are," Which is a famous quote from a movie featuring a leader motivating his team. Can you guess the movie quote?
Here's the finished work:

The picture is a well-known mentor/master from a well-known movie series.

What all these three guys have in common is that they are all fictional Leaders and Mentors in their universes. I think the quote will be the hardest one to figure out.