Just north of Corinth was a city named Eleusis. This was the location of a pagan religion where baptism in the sea was practiced to guarantee a good afterlife. This religion was mentioned by Homer in Hymn to Demeter 478-79.
1 The Corinthians were known to be heavily influenced by other customs. After all, they were in a large economic area where a great many different people frequented. It is probable that the Corinthians were being influenced by the religious practices found at Eleusis where baptism for the dead was practiced.
Paul used this example from the pagans in
1 Cor. 15:29, when he said, "...if the dead are not raised, then why are
they baptized for the dead?" Paul did not say
we.
2
This is significant because the Christian church was not practicing baptism for the dead, but the pagans were.
Paul's point was simple. The resurrection is a reality. It is going to happen when Jesus returns. Even the pagans believe in the resurrection, otherwise, why would
they baptize for the dead?
However, some are not convinced by this argument and state that the word "they" is not in the Greek and, therefore, Paul is not speaking about the pagans. Let's take a look.
Literally, the verse is translated as "Since what will do the being immersed on behalf of the dead if wholly dead not are raised why also are they immersed on behalf of them."
The issue here is the word, "baptizontai" -- "they are baptized." It is the present, passive, indicative, 3rd person, plural. In other words, it is THEY ARE BEING BAPTIZED or, THEY ARE BAPTIZED.
I -- first person singular
you (singular) -- second person singular
he/she/it -- third person singular
we -- first person plural
you (plural) -- second person plural
they -- third person plural
It is the latter form, the third person plural (they) in which the verb "baptizo" is found. Therefore, the best translation is "THEY are baptized."