1 Corinthians 15:29 Else what shall they do which are baptized for the dead, if the dead rise not at all?
The only group of which I am aware which practices baptism for dead ancestors are the Mormons. The Mormon doctrine of proxy baptism rests on this one passage in the entire Bible. Any doctrine must be suspect which rests on only one verse. Much more so when the interpretation given to the verses violates the teaching of Scripture that after death comes either judgment (if responsible) or annihilation (if not responsible). "It is appointed unto men once to die, but after this the judgment . . ." (Heb. 9:27).
But what does 1 Corinthians 15:29 mean? A number of interpretations have in the past been proposed. The one which best fits the context is the following:
"Else what shall they do which are baptized for the dead [Christ]5, if the dead [believers] rise not at all?"
The argument is: "Why be baptized on behalf of Christ who has not risen from the dead?" (cf. vs. 4-19; vs. 20-28 being read as parenthetical).
Here is some information from the website on the topic of baptism (please click on the title):
I hope you have found this helpful.