“Else what shall they do which are baptized for the dead, if the dead rise not at all? Why are they then baptized for the dead?” (1 Cor. 15:29).
It should be carefully noted that this verse is connected with verse 19, the verses between (vss. 20-28) being a parenthesis. “If in this life only,” says the Apostle, “we have hope in Christ, we are of all men most miserable,” that is, if there be no resurrection of the dead. He further goes on to say, “Else what shall they do which are baptized for the dead, if the dead rise not at all?” It would be folly to take the place of danger and liability to death through persecution (see vss. 30-32) if there be no prospect of resurrection. It is this which gives the key to the difficult expression “baptized for the dead.” Through the perils incident to the confession of Christ in those early days, martyrdom was of frequent occurrence. The ranks of Christians were thus continually thinned, but through the grace of God converts were constantly added, and in this scripture they are regarded as filling up the vacant places of those who had departed to be with Christ, and thus, when they were baptized unto Christ, as being baptized for or “over” (see note to JND translation).
E. Dennett