If you were to read the commentary on this verse in The People’s Bible (1 Corinthians, pages 149-150), you would find this: “Our first impression is that early Christians practiced vicarious baptism; one person could be baptized for another and thus could transfer his salvation to another. But the Bible clearly teaches that each person is saved by his own baptism and by his own faith. A God-fearing mother cannot believe or be baptized for a godless son.
“If it was not a vicarious baptism that Paul had in mind, then what was the practice he was referring to? More than three hundred different interpretations of this passage have been offered. Several of the interpretations that put the best construction on the practice are: 1) The relative of a Christian who has died may wish to be baptized in order to see this Christian again; 2) He may want to express the hope that a Christian friend who had died will rise; 3) The baptism and the godly life and final death of their friends in the sure hope of a blessed resurrection prompt the living also to desire and receive baptism for the same blessed purpose.
“In any event, even if there was a baptism for the dead that was prompted by the false notion that the baptism of a living person would benefit an ungodly person already dead (baptism by proxy), the practice would have been meaningless if the dead don’t rise. By referring to such an unscriptural practice (if, indeed, it existed) Paul was not condoning it. He was simply stating that even such a custom was a testimony to the reality of the resurrection.”
In summary, the apostle Paul speaks of a practice of which the Christians in Corinth were aware, but we today are not. That leaves us with questions—unanswered questions. Regardless of the unknown practice, the emphasis in that verse and throughout the entire fifteenth chapter is on Jesus’ physical resurrection from the dead. There is no uncertainty about that event. Many eyewitnesses saw the risen Lord. Earlier in 1 Corinthians 15 Paul listed some of those eyewitnesses.
The People’s Bible series offers explanation and commentary on all the books of the Bible. Your church library may have that series. The series is also available through Northwestern Publishing House.