God's command to Jonah to proclaim a specific message to Nineveh. The term emphasizes public declaration and authoritative announcement - not private conversation but open proclamation. Jonah was to speak not his own words but 'the proclamation that I tell you,' making him herald of divine judgment. This highlights prophetic office: prophets don't invent messages but transmit them. The word's root relates to calling or summoning, suggesting proclamation that demands response. Nineveh needed to hear God's word, and Jonah was the designated voice, however reluctant. Prophecy is proclamation - public, authoritative, inescapable.