Invincibility is in oneself, ...

Invincibility is in oneself, and vulnerability is in the opponent. Invincibility is a matter of defense, vulnerability is a matter of attack. Therefore skillful warriors are able to be invincible, but they cannot cause opponents to be vulnerable. That is why it is said that victory is discerned and not manufactured.
Invincibility is in oneself, and vulnerability is in the opponent. Invincibility is a matter of defense, vulnerability is a matter of attack. Therefore skillful warriors are able to be invincible, but they cannot cause opponents to be vulnerable. That is why it is said that victory is discerned and not manufactured.

Quotes from the same author

You have to believe in yourself.
Can you imagine what I would do if I could do all I can?
The supreme art of war is to subdue the enemy without fighting.
“Victorious warriors win first and then go to war, while defeated warriors go to war first and then seek to win.”
“Let your plans be dark and as impenetrable as night, and when you move, fall like a thunderbolt.”