When in the arena,
Yield not to an aggressor.
When outside the arena,
This world and this society are competitive. Tao uses the metaphor of the warrior to meet that competition. Warriors never yield to their opponents. They may sidestep, but they do not give way.
Whether you are a lawyer, police officer, fire fighter, doctor, businessperson, athlete, or any one of numerous other professions, you compete against either other people or natural forces. But there is a right way and a wrong way to compete. Avoid anger and greed. Use concentration and awareness.
Coincidentally, concentration and awareness are also necessary for spirituality. That is why the follower of Tao incorporates the way of the warrior into training. The warrior and the sage both seek to transcend emotion and petty thinking, to perfect themselves, and to live lives of the deepest truth.
But when outside the arena, do not forget to be kind. Leave behind competitive aggression. You must still have awareness, concentration, and reflex, but the expression will be different. Your compassion must not falter. That is why the combination of the way of the warrior with the way of Tao is the ultimate symbol of versatility. Such a follower of Tao commands the extremes of the universe.