महाभारत - शान्ति - आत्म जेयः

आत्मा जेयः सदा राज्ञा ततो जेयाश्च शत्रवः ।
अजितात्मा नरपतिर्विजयेत कथं रिपून् ॥

- महाभारत, शान्ति

aatma jeyaH sadA rAjnA tato jeyashcha shatravaH ।
ajitAtmA narapatiH vijayeta katham ripUn ॥

- mahAbhArata, shAnti

One must defeat himself (senses) first. Then he can think about defeating his enemies. If one can not defeat his own senses how can he defeat external enemies?

- Mahabharata, Shanti