How to Establish God's Kingdom on Earth

According to T. D. Alexander in the book From Eden to the New Jerusalem:

By living in obedience to Christ, his disciples participate in the establishment of God's kingdom on earth. This kingdom is not restricted by national boundaries, but is gradually expanding to fill the whole earth. Yet, although this divine kingdom continues to grow, with more and more people acknowledging the supreme sovereignty of God, many of the earth's inhabitants defiantly refuse to enthrone God as their Lord.