A river.
Two princes are taken out to the woods by their father and tested on their patience. They are told that they will be left in the forest and the owner of the horse who arrives home last will become the next king. The princes meander and forage in the woods for hours, into days, into a week. Now near death the princes come across the hut of a wise hermit. The hermit feeds the princes, mends their clothes and, upon hearing of their predicament, says two words to the young princes. After hearing these two words the two Princes race home as fast as possible.
What two words did the hermit say?