In various Old Testament passages where the image of fire is used, it most naturally seen as a destructive force, and it describes the judgment of God on his enemies (Isaiah 5:24, 10:17; Zechariah 11:1, 12:6; Jeremiah 17:4). But fire is also used in a positive way, and its refining effects are drawn attention to (Isaiah 4:4; Malachi 3:2; 1 Corinthians 3:13).
A fire is not a thunderbolt. We are not speaking here of the final day of judgment when at a stroke the world will end and everyone will come before God. We’re talking about something much slower. We're talking about fields of stubble and a fire is kindled here and there in the field and gradually it spreads across the field. And that is the picture language here. Before that final end the people of God, the church of Jesus Christ, will be as a fire. Jacob, he was oppressed. Joseph, he was even more oppressed. But this suffering church, this despised people of God, looked down upon from the world, will set light to the stubble here and there, down the generations. This fire will gradually go through the world and people from every land and nation will be turned to Jesus Christ. Not the majority of them but out of every land and nation God will take people for his own possession and bless them and save them and make them his own. Matthew Henry explains, ‘When the idols and idolatry were abolished, and the wealth and power of the nations were brought into the service of Christ and his gospel, and the spoils of the strong man armed were divided by him that was stronger than he, then [in the language of prophecy] the house of Jacob and Joseph devoured the house of Esau, so that there was none of them left remaining.’ Finally the judgment will fall and the world will be destroyed and rejuvenated and it will be God's forever.