John Piper on Mission

"Three billion people today are outside Jesus Christ. Two-thirds of them have no viable Christian witness in their culture. If they are to hear ? and Christ commands that they hear ? then cross-cultural missionaries will have to be sent and paid for. All the wealth needed to send this new army of good news ambassadors is already in the church. If we, like Paul, are content with the simple necessities of life, hundreds of millions of dollars in the church would be released to take the gospel to the frontiers. The revolution of joy and freedom it would cause at home would be the best local witness imaginable." (Desiring God, pp. 166-67)