The nations in chs. 46—51 typify nine different aspects of the world. Just as Israel as God’s Old Testament elect was involved with the nations, the church as God’s New Testament elect is involved with the world in its many aspects. Jeremiah presents a vivid picture of God’s punishment and judgment on the nations so that we may know how to have a clear separation from the world and not be mixed with any of its aspects (John 12:31; 17:14-21; Gal. 6:14; 2 Pet. 1:4; 1 John 2:15-17). God will come in to judge the world in all its aspects and to make a clear distinction between the church, which is today’s Israel (Gal. 6:16 and note Gal. 6:164c), and every aspect of the world.
Jeremiah prophesied concerning the nations because in His economy God needs them. On the one hand, God needs His chosen people to express Him; on the other hand, He needs another people, the nations, to behold and admire this expression, which is His masterpiece (Eph. 2:10), the New Jerusalem. The nations around the New Jerusalem in the new heaven and new earth (Rev. 21:24, 26; 22:2b) will eventually come from the nations concerning which Jeremiah and other Old Testament prophets prophesied.