I pray for them. I am not praying for the world, but for those you have given me, for they are yours (Jn.17.9 NIV).

Ever since the promise of redemption contained in the sentence, or curse, upon the devil (Gen. 3.15), two kingdoms have existed: The seed of woman and the seed of the serpent. It is not the case, however, that God only rules one of those kingdoms: For you granted him authority over all people that he might give eternal life to all those you have given him (Jn. 17.2 NIV). No dualism exists that pits the devil and God as any kind of equals. In fact, Jesus is the creator of these fallen spiritual entities: For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him (Col. 1.6 NIV).

Another scripture that vividly describe these two kingdoms is Col. 1.13: for he has rescued us from the dominion of darkness and brought us into the kingdom of the Son he loves (NIV). While in Colossians the created, though fallen, kingdom is described as “the dominion of darkness,” in other places it is referenced as “death:” Very truly I tell you, whoever hears my word and believes him who sent me has eternal life and will not be judged but has crossed over from death to life (Jn. 5.24 NIV). These terms are, of course, equivalent since scripture communicates concepts and not just bare terms.

These two kingdoms can be differentiated by the character of its community, namely, if the members reflect love: We know that we have passed from death to life, because we love each other. Anyone who does not love remains in death (1Jn. 3.14 NIV).

Additionally, these earthly and temporal kingdoms are asymmetric as to their size. Jesus labeled these two paths as broad and narrow: Enter through the narrow gate. For wide is the gate and broad is the road that leads to destruction, and many enter through it. But small is the gate and narrow the road that leads to life, and only a few find it (Mt. 7.13-14 NIV). The bible records the struggle of the redeemed in the world of darkness and is the Christian’s guide to navigating their earthly journey. Through the scriptures we see that God has always blessed His people and protected them. God will continue His oversight of believers since Jesus prayed for their protection: My prayer is not that you take them out of the world but that you protect them from the evil one (Jn. 17.15 NIV).

Here is a journal article that summarizes the thoughts of the Two Kingdoms approach of proponents and their critics. I support the view of Two Kingdoms over against the Kuyparian position(see Abraham Kuyper 1837-1920).

The Resurgence of Two Kingdoms Doctrine: A Survey of the Literature – The Gospel Coalition