Lightness is not just physical, but also spiritual.

The cowards never started and the weak died along the way. That leaves us.

解释：影子的弯曲与正直是随身体而变化的，根源不在影子自身；自己的屈曲与伸直是随外物而变化的，而不在于个人的主观意志。这就是保持谦退才能使自己处世为先的道理。