This comes from Zhuge Liang, one of the most important and renown strategists of Chinese history.
"夫君子之行：静以修身，俭以养德；非淡泊无以明志，非宁静无以致远。" - 诸葛亮
One should seek serenity to cultivate the body, thriftiness to cultivate the morals. Seeking fame and wealth will not lead to noble ideal. Only by seeking serenity will one reach far. - Zhuge Liang
Source - China History Forum