Canonical Reference: Dhp 103 Verified Source

“Though one may conquer a thousand times a thousand men in battle, yet he indeed is the noblest victor who conquers himself.”

— Gautam Buddha
The Awakened One, Founder of Dhamma
Historical Setting & Context:

Pali Canon: Dhammapada 8.103 (Yo sahassaṁ sahassena, saṅgāme mānuse jine; Ekañca jeyyamattānaṁ, sa ve saṅgāmajuttamo).