Hi,
First Cor 15 is concerned with the immortality of the body and soul. In verses 24-26 he writes that when Christ hands over the kingdom to the Father. the last off the enemies to be destroyed is death.
Then he says; “If this were not true, what do people hope to gain by being baptized for the dead?” This is a strange question. There is nothing comparable anywhere else in the New Testament. “A Catholic Commentary on Holy Scripture states” The meaning is very doubtful. Perhaps some persons at Corinth had desired to become Christians but had been overtaken by death before they could be baptized and Christian friends had been allowed to undergo a (purely symbolic) baptism for them to show that the dead were counted as Christians. If so, the practice was soon dropped for fear of misunderstanding."
Fr. Vincent Serpa, O.P.