I include a quotation from the chapter by Richard John Neuhaus:
In acknowledging one another as Christians, we have already taken a very major ecumenical step. That is, we understand ourselves to be living in the same . . . world of faith. “So then you are no longer strangers and sojourners, but you are fellow citizens with the saints and members of the household of God, built upon the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone.” (Eph. 2: 19=20)