And you, child, will be called a prophet of the Most High, For you will go before the face of the Lord to make ready his ways,
Go before the face of the Lord ...  These words are an elaboration of the prophecy in  Malachi 4:5,6.  The imagery is that of a herald going before a king to prepare the way for a royal visitor.  Here too the subordination of John, the child of hope, to the royal dignity of the yet unborn Christ (by these words of Zacharias) is contrary to all human behavior and must be attributed solely to the inspiration of the prophet Zacharias by the Holy Spirit.