Authors:

Karate is like boiling water: without heat, it returns to it's tepid state

Gichin Funakoshi, Genwa Nakasone, Jotaro Takagi (2003). “空手道二十訓: The Spiritual Legacy of the Master”, p.126, Kodansha International
Karate is like boiling water: without heat, it returns to it's tepid state