Does the walker choose the path, or the path the walker? - Garth Nix

Sam swallowed. The dire pronouncement echoed in his ears, imbued with the faint hint of the Free Magic power that was contained within the cat form on his shoulder. He slapped Sprout on the rump to get her going; then he said the first thing that came into his head. "Mogget. Shut up."

"Choosers will be beggars if the begging’s not their choosing," said the Dog.

"I don't... I don't care," he said softly to his reflection. "I have a job to do. It doesn't matter what I have become. It doesn't matter what I look like."