Yamamoto Tsunetomo

我が智慧の一分の智慧計かりにて萬事をなす故、私と成り天道に背き、悪事となる也。

Because we do most things relying only on our own sagacity we become self-interested, turn our backs on reason, and things do not turn out well.

http://forum.jisho.org/discussion/3851/%E5%A4%A9%E3%81%AE%E9%81%93/p1