It's separating two choices:
1. Change yourself
2. Change the world
Those that want to change the world, make people do things their way, or make themselves elevated in the eyes of society or friends, are changing the world.
That is why people who change themselves are stronger, because their greatest enemy is always themselves. And they can change themselves a lot faster than they can change the world.
For example, when a person is confronted with a problem such as a wall in their way, the person that chooses to change himself will change his route or direction and find a way around the wall. The person that wants to change the world, will then change the wall by drilling through it, knocking it over, or getting someone else to move them past the wall by pushing the car while they drive.
Thus in martial arts, this is exemplified in two ways of thinking, the external way and the internal way. External power thus comes from using power to change what's around you, powering through obstacles. Internal power is taking in power from the world, changing it inside yourself, and making better use of what you have rather than what you don't have.
In external schools, this line would mean that as you punch the wall, visually and mentally you are fighting and overcoming yourself, not the wall. Because if your image is wrong, your technique will become wrong, and the hand breaks, not the wall.
In internal schools, this means to develop power and ability by focusing on one's own body, rather than on what external society says is right or wrong. So instead of focusing on beat other people to win, they should focus on beating themselves.
it mean To overcome yourself you have to become stronger than yourself.
I assume it means to become a better person than you were you must grow as a person or become "stronger"
It is to do with mental strenght and attitude you need to train your mind just as you train your body develop mental awareness and understanding and be at one with your surroundings inner peace leads to outer strenght
overcome your challenges.
To overcome yourself you have to become stronger than yourself.
