When a prophetic message is delivered to the leadership of the people, the order in which the leaders are addressed carries a specific and intentional meaning. The prophet is instructed to speak first to Zerubbabel, and only afterward to Joshua the High Priest. This sequence establishes a clear and proper hierarchy among the nation's figures of authority.
According to traditional rules of respect, the institution of royalty is always honored above both the priesthood and the prophets. Because Zerubbabel traces his lineage directly back to the royal house, being a descendant of King Jehoiachin, he is given the place of primary honor and receives the message before the High Priest [אבן עזרא].