Buddha

"Peace comes from within. Do not seek it without."

"The foolish man conceives the idea of 'self.' The wise man sees there is no ground on which to build the idea of 'self;' thus, he has a right conception of the world and well concludes that all compounds amassed by sorrow will be dissolved again, but the truth will remain."

"Do not dwell in the past, do not dream of the future, concentrate the mind on the present moment."