The motive for missions is the concern for telling others that God has shown the grace to all. Take the example of St. Paul. He had to witness for he saw a world of people who had not heard the "good news." The church knows that God does not fail to show His grace. The church must proclaim... A true missionary can never believe that those who refuse the Gospel can really refuse. He does not know on what ground the seed falls. Only then can a missionary be really free. He is only an ambassador, not the king.
John D. Godsey,Karl Barth's Table Talk, p. 40.