Else what shall they do which are baptized for [on behalf of, in place of, instead of] the dead [plural, “dead ones”], if the dead rise not at all? why are they then baptized for the dead?
It’s important to understand what this verse does not teach. Water baptism does not save anybody
Problem: The Bible seems to claim here that Christ was the first one ever to rise from the dead, calling Him “the firstfruits of those who have fallen asleep.” However, there are many other resurrections recorded in the Bible before Jesus’ resurrection, both in the OT (cf. 1 Kings 17:22; 2 Kings 13:21) and in the NT (cf. John 11:43–44; Acts 20:9). How then could Jesus’ resurrection be the first one.