Study only death

A recluse came and asked: “What is the primary concern in religious practice?”

The Master responded: “Put everything aside and only study death. Always study death, free yourself from death, and when death really comes you will not be flustered. In order to save others, knowledge is necessary. For your own salvation, however, whatever knowledge you have grasped becomes your enemy. Just be mindless as earth; recite the nenbutsu (praise to Amida Buddha) and study death.”

Suzuki Shosan (1579 –1655)
From Warrior Zen – The Diamond-hard Wisdom Mind of Suzuki Shosan