“I have chosen Mr. Baggins and that ought to be enough for all of you. If I say he is a Burglar, a Burglar he is, or will be when the time comes. There is a lot more in him than you guess, and a deal more than he has any idea of himself.”
Strider hides behind the hedge on the Road west of Bree and eavesdrops on "Mr. Underhill". In the inn Frodo arouses attention by his sudden disappearance whereupon Strider warns him to be more careful and reveals himself as being Gandalf's friend.