Though the fullness of reigning will become reality in the New Jerusalem, God has set his people to be kings already in today’s world. There is no place for selfishness—and hence exploitation (of nature or of other people)—as God’s people have a place with God and the Lamb on his throne. The (unbelieving) world benefits greatly from saintly kings fulfilling their office in a godly fashion.
5 And night will be no more. They will need no light of lamp or sun, for the Lord God will be their light, and they will reign forever and ever.