Sahih Bukhari Volume 005, Book 058, Hadith Number 123.

Narated By Abu Huraira : The Prophet or Abul-Qasim said, "If the Ansar took their way through a valley or a mountain pass, I would take Ansar's valley. And but for the migration, I would have been one of the Ansar." Abu Huraira used to say, "The Prophet is not unjust (by saying so). May my parents be sacrificed for him, for the Ansar sheltered and helped him," or said a similar sentence.