God requires no person to spend his or her life reiterating the gospel to people who will not receive it. He wants everyone to have an opportunity to hear. Then He would have us move on to other areas. The mistake of the church has been that she sits down to convert all the people in one country to the neglect of the great masses who have never had the chance to hear the gospel - not even once!
A. B. Simpson (1987). “Missionary Messages: For a Church that Needs to Hear”, p.17, Moody Publishers