We don’t know exactly what Paul meant by when he wrote, “Else what shall they do that are baptized for the dead? If the dead are not raised at all, why then are they baptized for them?” (1 Corinthians 15:29)
St. Francis de Sales lived after the start of the protestant revolt. He wrote
Catholic Controversies as a defense of Catholic doctrine. In chapter 5 about purgatory, he refers to 2 Maccabees 12:43-45, where Judas Maccabee gives two thousand drachmas of silver as an offering for the sins of the dead. Judas concludes with,
Therefore he made atonement for the dead, that they might be delivered from their sin. While Protestants reject the apocryphal books, Francis says, “But if, in the very last resort, we would take it as the testimony of a simple but great historian- which cannot be refused us-
we must at least confess that the ancient synagogue believed in Purgatory, since all that army was so prompt to pray for the departed.”
Francis says, “And truly we have marks of this devotion in other Scriptures which ought to make easier to us the reception of the passage which we have just adduced. In Tobias, chap. iv.[Tobias 4:18]:
Lay out thy bread and thy wine on the burial of a just man; and do not eat or drink thereof with the wicked.”
Francis says, “And of this custom S. Paul speaks quite clearly in the 1st of Corinthians chap xv.[1 Corinthians 15:29], appealing to it as praiseworthy and right. What shall they do who are baptized for the dead if the dead rise not again at all? Why then are they baptized for them?
This passage properly understood evidently shows that it was the custom of the primitive Church to watch, pray, fast, for the souls of the departed.”
Francis continues, “in the Scriptures to be baptized is often taken for afflictions and penances; as in S. Luke, chap xii.[Luke 12:50], where Our Lord speaking of his Passion says:
I have a baptism wherewith I am to be baptized and how am I straitened until it be accomplished!-and in S. Mark. chap x.[Mark 10:38], he says :
Can you drink of the chalice that I drink of; or be baptized with the baptism wherewith I am baptized? -in which places Our Lord calls pains and afflictions baptism. This then is the sense of that Scripture: if the dead rise not again, what is the use of mortifying and afflicting oneself, of praying and fasting for the dead? And indeed this sentence of S. Paul resembles that of Machabees quoted above: It is superfluous and vain to pray for the dead if the dead rise not again. They may twist and transform this text with as many interpretations as they like, and there will be none to properly fit into the Holy Letter except this.
But [secondly] it must not be said that the baptism of which S. Paul speaks is only a baptism of grief and tears, and not of fasts, prayers, and other works. For thus understood his conclusion would be very false. The conclusion he means to draw is that if the dead rise not again, and if the soul is mortal, in vain do we afflict ourselves for the dead. But, I pray you, should we not have more occasion to afflict ourselves by sadness for the death of friends if they rise no more - losing all hope of ever seeing them again - than if they do rise? He refers then to the voluntary afflictions which they undertook to impetrate the repose of the departed, which, questionless, would be undergone in vain if souls were mortal and the dead rose not again. Wherein we must keep in mind what was said above, that the article of the resurrection of the dead and that of the immortality of the soul were so joined together in the belief of the Jews that he who acknowledged the one acknowledged the other, and he who denied the one denied the other. It appears then by these words of S. Paul that prayer, fasting, and other holy afflictions were practiced for the departed. Now it was not for those in Paradise, who had no need of it, nor for those in hell, who could get no benefit from it; it was, then, for those in Purgatory. Thus did S. Ephrem expound it twelve hundred years ago, and so did the Fathers who disputed against the Petrobusians.”
So instead of restoring the ancient belief in purgatory and prayers that are given for the souls there, Joseph Smith invented proxy water baptism on behalf of the dead. A practice never used by Christians. Mormonism is an invention not a restoration.