One may conquer a million men in a single battle;
However, the greatest and best warrior
Conquest of one's self is the greatest victory of all.
Neither a god nor a heavenly musician
Nor a mischievous angel
Of the highest of the six heavenly abodes-
The Paranimmita-heaven, where sensual pleasures prevail-
Can deprive the self-vanquished, restrained person of victory.
-the Dhammapada, 8 Φ Thousands
Another great teaching from the Buddha that the big leaders of the world, and all the rest of us, can benefit from.