It's possible. Les Brown on Roger Bannister

It's possible.
Saying that to yourself everyday will change your belief system.

“Most people operate out of their personal history, out of their memory,
things they’ve done, things they’ve experienced, things they’ve seen, things that they have observed.

What I’m suggesting is that you operate out of a larger vision of yourself, I want you to see yourself doing what you want to do, experiencing what you want to experience, having what you want to have, doing what it is that gives your life some meaning and value, operate out of your imagination not your memory.”

From the speech of Les Brown - It's possible.

Operate out of your imagination, not your memory.

Before April 8th 1954 [It seems it was 6th of May], the common belief, the universal belief, (because it had been tried, again and again and again and again, and people had failed), the belief was that man was physically not capable of breaking the 4 minute barrier, that he could not run a mile in less than 4 minutes. That was the belief. On the planet. It had never been done...

But here's what happened, ladies and gentlemen: Roger Bannister came along. And he broke the 4 minute barrier. Now here's what's significant about that. Since that time, up to this day, over 20.000 people have done it, including high-school kids! What changed?
  Here's what happened when they got on the track: they knew it had been done! And because they knew it had been done, there was a new belief about this barrier, about this goal that was "unreachable". And those 20.000 people got in the race believing, knowing in their hart that someone had done it, that IT'S POSSIBLE, that they could do it.

And I'm saying that if you know anybody that had some goals, some dreams, something they wanted to do ... and they did it, then I'm saying that you know it in your heart that if someone has done it, than you can do it. It's possible.
  And that if someone can make their dream become a reality, that it's possible; that you can make your dream become a reality.

And so as you begin to look at where you want to go, beginning to embrace that it's possible.
/.../ I got a lot going for me, I got some good stuff in me. And it's possible that I can get my greatness out here in the universe. That I can do what I want to do, it's possible:
I can write my own book,
I can have my own business,
I ... I can take the trip and travel around the world: it's possible!
I can bounce back from adversity and re-invent my life: it's possible!
Regardless of where I am: that things can get better for me: ... it's possible!

Again from the speech: Les Brown - It's possible.

(Funny story: someone also copied this text (I copied some of it from there), but wrote: "be able to run faster than 4 minutes in a 100 mile run". I don't know whether 100 miles is synonymous with 1 mile, but I am guessing this person was not an experienced runner.)

So remember Roger Bannister. What changed? Belief that it is possible.

... Until one day in 1952 after Sir Roger Bannister had beat the current mark, but was still 4 seconds longer then breaking the 4 minute barrier. However, something clearly changed in his mind, “This race made me realize that the four-minute mile was not out of reach,”. Sir Roger Bannister’s new belief had given birth to the fastest 100 mile run on the planet. To elaborate on the subject, people had called it the “miracle mile” and Bannister remarked on the event stating that “No longer conscious of my movement, I discovered a new unity with nature. I had found a new source of power and beauty, a source I never dreamt existed.” 

From: here.

P.S.:  Bannister's record was broken in just 46 days by John Landy, now known as the Miracle Mile.
P.P.S.: He reclaimed the world record again in 3 years.
PPPS- Before Bannister, the record apparently held for 9 years. The current record (in men's category) is held since 1999 by a guy from Morocco, with a 3:43 on the clock. (Yeah, don't forget the women, eh.)