Luke 7:7

Wherefore neither thought I myself worthy to come unto thee: but say a word, and my servant shall be healed.

 The centurion understood the authority Jesus had on this earth.  He believed the word that Jesus spoke, and his faith in that word caused his servant to be healed.  We can operate on this earth in that same belief.  Our faith in the word and works of Jesus, without doubt, will manifest miracles.  Faith believes and speaks only one option, and that is what the word says