Lord Buddha

“Greater in battle
than the man who would conquer
a thousand-thousand men,
is he who would conquer
just one —
himself.
Better to conquer yourself
than others.
When you've trained yourself,
living in constant self-control,
neither a deva nor gandhabba,
nor a Mara banded with Brahmas,
could turn that triumph
back into defeat.” 
― Gautama Buddha