[Monkey] had to learn the lesson of humility by an ultimate bet with Buddha or God Himself. He made a bet that with his magical powers he could go as far as the end of the earth, and the stake was the title of "The Great Sage, Equal of Heaven," or else complete submission. Then he leaped into the air, and traveled with lightning speed across the continents until he came to a mountain with five peaks, which he thought must be as far as mortal beings had ever set foot. In order to leave a record of his having reached the place, he passed some monkey urine at the foot of the middle peak, and having satisfied himself with this feat, he came back and told Buddha about his journey. Buddha then opened one hand and asked him to smell his own urine at the base of the middle finger, and told him how all this time he had never left the palm.
Wu Cheng'en