Because we cannot accept the truth of transience, we suffer.
Time goes from present to past.
There is no need to have a deep understanding of Zen.
All descriptions of reality are limited expressions of the world of emptiness. Yet we attach to the descriptions and think they are reality. That is a mistake.
Discipline is creating the situation.
A tiger does not ignore or slight any small animal. The way he catches a mouse and catches and devours a cow are the same.