Formerly, before God began to work in this way, there were two kinds of people on earth: the converted and unconverted. However, let us be a little bit more specific. In the context of Ephesians 2, the two kinds of people were Israelites and Gentiles. When we understand verses 16-20, He is saying now a third class of people is arising. There is the Gentile, the Israelite, and the Christian—the new man.
This is what God is creating, a family, a nation. He is creating something that is unique on the earth: a family that gets along with each other. Such a thing is unseen in the history of men. There are no wars (considering nations being families grown great) that are more vicious and terrible than inter-family wars, which we call "civil wars."
God is creating a family that gets along with each other, and this harmony begins with the acceptance of the blood of Jesus Christ. However, God expects that it will not end there. Because of the fellowship that we have with Him through Jesus Christ, as we begin to have more things in common, it will begin to expand out to others whom He is calling. It begins with the Spirit of God working with the person and eventually in him.
John W. Ritenbaugh
Truth (Part 4)