“What will those do who are baptized for the dead? If the dead are not raised at all, why then are they baptized for them?” (1 Corinthians 15:29).
The fact of the Resurrection often is a powerful testimony to draw people to saving faith in Christ.
The apostle Paul knew that believers who face death with joy and hope can present powerful testimonies to unbelievers. The prospect of life in Heaven and a reunion with loved ones is a strong motive for people to hear and receive the gospel. When believers die, their spirits go immediately to be with the Lord. And one day in the future their glorified bodies will rejoin their spirits, and Christians will worship and enjoy God for all eternity.
First Corinthians 15:29 uses the term “baptized” to refer to those who were testifying that they were Christians. Although the mere act of baptism does not save a person, anyone who is an obedient Christian will be baptized. In Paul’s day, the church assumed that any believer would have been baptized, and people were not baptized unless the church was confident their profession of faith was genuine.
“The dead” in 1 Corinthians 15:29 could also include believers, those who have died and whose lives were persuasive testimonies to the life, death, and resurrection of Jesus Christ. People were being saved (baptized) in Corinth because of (“for”) the faithful witness of deceased believers.
The Resurrection is still a powerful incentive to salvation. In my years as a pastor I have seen people come to Christ after the death of a believing spouse or parent. Those husbands and wives, sons and daughters could not bear the thought of never seeing their loved one again. Those converted survivors were unknowingly touched and changed by the reunion hope that already sustains believers. That hope, based on the promise of resurrection, upheld David after the death of his infant son: “I shall go to him, but he will not return to me” (2 Sam. 12:23).