戰國?老子《道德經》
The one who knows well about others is only a smart guy, whereas the one who understands himself is the sensible Solomon.
The one who could defeat others is just a strong man, whereas the one who could win over his evil in mind (心魔) himself is really a powerful one.
Quoted from the work as Tao Te Ching (或意譯：Canon of Morality) by Lao-tse (或：Laozi、Li Er，李耳) during the Warring States period in ancient China