Paul speaks of baptism “for the dead” in a context in which he is defending the doctrine of the resurrection of the dead at the last day. Some of the Corinthians apparently had denied that there would be such a resurrection, as we see from verse 12.
Now if Christ is proclaimed as raised from the dead, how can some of you say that there is no resurrection of the dead? (1 Cor. 15:12)This skepticism concerning the resurrection also appeared while Paul was preaching in Athens in Acts 17. Scripture says that some of his hearers mocked him when he mentioned the resurrection of the dead (Acts 17:32).
This skepticism apparently infected some in the church at Corinth as well. And then he proceeds to defend the resurrection against those who for whatever reason denied it.
One of the points that he brings up in defense of the resurrection is the practice of baptism on behalf of the dead.
What do people mean by being baptized on behalf of the dead? If the dead are not raised at all, why are people baptized on their behalf? (1 Cor. 15:9)The Greek phrase which is translated “on behalf of the dead” may also be translated “with reference to the dead” or “on account of the dead.”
Many scholars have assumed that Paul was talking about some early heretical practice that was rooted in a pagan ritual—a practice that he doesn’t necessarily agree with or approve, but one that he finds helpful to his argument nonetheless.
It seems to me rather that Paul has in mind an Old Testament ritual washing that was commanded for those who had contact with a dead body. We read about this in the book of Numbers. The Lord says,
Whoever touches the dead body of any person shall be unclean seven days. He shall cleanse himself with the water on the third day and on the seventh day, and so be clean. But if he does not cleanse himself on the third day and on the seventh day, he will not become clean. Whoever touches a dead person, the body of anyone who has died, and does not cleanse himself, defiles the tabernacle of the LORD, and that person shall be cut off from Israel; because the water for impurity was not thrown [sprinkled] on him, he shall be unclean. His uncleanness is still on him (Num. 19:11-13)This passage is referred to in the 9th chapter of Hebrews. Guess what the washing with water is called. Baptism! In speaking about the nature of things under the Old Testament law of purification, and after referring to Numbers 19, Paul says,
Gifts and sacrifices are offered that cannot perfect the conscience of the worshiper, but deal only with food and drink and various washings [baptismos] (Heb. 9:10)This is not the only place in the New Testament where the ritual washings of the Old Testament are referred to as baptisms. We have another instance in Mark 7.
Now when the Pharisees gathered to him, with some of the scribes who had come from Jerusalem, they saw that some of his disciples ate with hands that were defiled, that is, unwashed. (For the Pharisees and all the Jews do not eat unless they wash [nipto] their hands, holding to the tradition of the elders, and when they come from the marketplace, they do not eat unless they wash [baptizo]. And there are many other traditions that they observe, such as the washing [baptismos] of cups and pots and copper vessels and dining couches.) (Mk. 7:1-4)We see, then, that the ritual washings of the OT are called baptisms. Moreover, there was a specific ritual washing—a specific baptism—which God commanded for those who had had contact with a dead body. This is what Paul is referring to, when he speaks of baptism on account of the dead. The Christian community in Corinth, being composed of Jews and of God-fearing Gentiles attached to the synagogue, would have been familiar with this practice.
And Paul is suggesting that this ritual washing on account of contact with a dead body presupposes the continued existence and future resurrection of the one who had died.