The nations are not gathered in automatically. If God has promised to bless "all the families of the earth," he has promised to do so "through Abraham's seed" (Genesis 12:3, 22:18). Now we are Abraham's seed by faith, and the earth's families will be blessed only if we go to them with the gospel. That is God's plain purpose.
John StottBecause in no other person but the historic Jesus of Nazareth has God become man and lived a human life on earth, died to bear the penalty of our sins, and been raised from death and exalted to glory, there is no other Savior, for there is no other person who is qualified to save.
John Stott