15:29 What is the meaning and purpose of baptism for the dead and is Paul validating the practice here?

Paul offers no opinion on whether being baptized for the dead is right or wrong here and there is no elaboration on the practice anywhere else in scripture so we cannot speculate on its meaning and purpose.

Paul is simply showing up the inconsistency of the Corinthians; they rejected the doctrine of the resurrection of the dead, yet embraced the practice of being baptized for the dead. It was a contradiction in terms - if there is no resurrection, why be concerned for the dead at all (CP V12 and V20 with V29).

Also, why would Paul risk death for the gospel's sake if there is no resurrection of the dead and this life was all there was. If there is no life to come Christians would be better off eating, drinking and being merry before they died (CP V19,30-32 with Jn 3:3-5; Ac 26:23; Ro 4:24-25; Eph 1:19-23; 1 Pe 1:3-5, 21).