Who said "The greatest enemy is often the one within ourselves."?

This quote is attributed to Wilhelm II.

The greatest enemy is often the one within ourselves. - Wilhelm II

"The greatest enemy is often the one within ourselves."

Wilhelm II Fear

Kaiser, Monarch German 1859–1941

"The fact that I am not always right is something of which I am well aware."

"We have fought this war like sissies and not like men."

"You will find that the the Americans only outwish us."

"I am the German Emperor, and I consider myself an instrument of the Lord."

"Face your fears with courage."

"You can't live your life in fear."

"Snakes. Why'd it have to be snakes?"

"Fear is just another obstacle to overcome."