Chapter 11, Verses 38 and 39 - Sun Tzu

At the critical moment, the leader of an army acts like one who has climbed up a height and then kicks away the ladder behind him. He carries his men deep into hostile territory before he shows his hand. He burns his boats and breaks his cooking-pots; like a shepherd driving a flock of sheep, he drives his men this way and that, and nothing knows whither he is going.
~ from The Art of War, Giles translation ~

Go here to read the introductory post to the verses of The Art of War.