How are believers supposed to serve in God's vineyard?
Believers serve as ambassadors for Christ, letting the world know they have already been reconciled to God. They are saved to serve, not to sit or merely escape hellfire, and are to be useful in God's vineyard in whatever capacity He assigns to each one.
Les explains that every Grace Age believer is an ambassador for Christ. Like an ambassador sent to a foreign country, the believer does not isolate himself but stays in communication with the home government, constantly feeding information back and forth. Our job is to let the world know they have already been reconciled—it is done, it is finished. Then, moving into chapter 6, Les teaches that God did not save us to sit or just to escape hellfire, but we are saved to serve. We are to be useful in God's vineyard in whatever particular capacity He may give to each one of us. The context also quotes Isaiah: “Behold, now is the accepted time; behold, now is the day of salvation.”