Please read St. John Chrysostom on this issue. The full text can be found hereI was talking to a gentleman that told me that one could be saved after death. He said that in 1st Corinthians 15:29 they were baptising for the death which would be an odd thing to do if one couldn’t be saved from the dead. What should I say to thing? Thanks and God bless.
What then is that which he means? Or will ye that I should first mention how they who are infected with the Marcionite heresy pervert this expression? And I know indeed that I shall excite much laughter; nevertheless, even on this account most of all I will mention it that you may the more completely avoid this disease: viz., when any Catechumen departs among them, having concealed the living man under the couch of the dead, they approach the corpse and talk with him, and ask him if he wishes to receive baptism; then when he makes no answer, he that is concealed underneath saith in his stead that of course he should wish to be baptized; and so they baptize him instead of the departed, like men jesting upon the stage. So great power hath the devil over the souls of careless sinners.
For the being baptized and immersed and then emerging, is a symbol of the descent into Hades and return thence. Wherefore also Paul calls baptism a burial, saying, “Therefore we are buried with Him by baptism into death.” (Rom. vi. 4.) By this he makes that also which is to come credible, I mean, the resurrection of our bodies. For the blotting out sins is a much greater thing than the raising up of a body.
This then he here saith of those who are baptized also. “What shall they do which are baptized,” saith he, “having subscribed to the resurrection of dead bodies, and not receiving it, but suffering fraud? And what need was there at all of this confession, if the fact did not follow?”