Commentators explain that the imagery of smoke from God's nostrils and devouring fire from His mouth is a powerful, poetic way to describe His intense indignation. This is not meant to suggest God has a physical body or human passions, but to use vivid, understandable language (anthropomorphism) to convey the awesome and terrifying nature of His righteous anger against evil and injustice. The imagery is drawn from powerful natural forces like thunderstorms.