Answer
Praying for people after they die does not make a difference with regard to their eternal state. The Bible gives us no indication that they have an opportunity to repent after they die; it suggests that they go straight to the judgment (Heb. 9:27). It also teaches us that those who do not have the gospel have no hope of being saved (e.g., Rom. 10:13ff.; Eph. 2:12). If they had an opportunity to repent and be saved after death, then they would still have some hope, even without hearing the gospel in this life.
We also have the story or parable of Lazarus and Dives (Luke 16:19-31). Some scholars argue that this story is based on Jewish mythology and therefore does not reflect the actual state of existence after death. Others argue that it is not a parable at all but a true account, for reasons such as the fact that the characters in the Jesus' other parables are not named, except for those that are actual and immediately recognizable (like God, the devil, etc.). As I see it, it is generally the case, with only this one possible exception, that Jesus' parables are true to life. Therefore, I see no reason that we should assume that this story is based on a false cosmology or an incorrect idea of the afterlife.
Assuming that it is faithful to reality, then it demonstrates that no opportunity to repent exists after death. Dives suffers in Hades and asks Abraham to send a preacher to his brothers. Dives does not recognize any hope for himself, nor does Abraham. On the contrary, Abraham confirms that Dives is now doomed to suffer his just deserts.
But even it if is not absolutely faithful to reality, the parable still depends to some degree on the gospel message being urgent, available in this life only. If an opportunity to repent existed after death, after we had already come to see firsthand the reality of the Bible's message, then it could hardly be said that Scripture itself is the most compelling gospel message of all. But the parable teaches that Scripture is the ultimate witness.
I would also point out that throughout Scripture the gospel message is presented as being urgent. If hope remained after death, this urgency would be severely blunted. We would expect someone somewhere to say something like, "But if they don't believe your message now, they may come to believe it when they die. Therefore, pray for them." Prayers are encouraged for everyone else, so the omission of prayers for the dead would be odd, if such were valid. Instead, what we find are situations like David ceasing to pray for his son once his son had died (2 Sam. 12).
Generally, prayers for the dead are offered in the context of a Roman Catholic understanding of purgatory, where intercessory prayers for the dead can reduce their time in purgatory. Since I don't believe in purgatory, I do not see this as a possible validation for prayers for the dead.
That being said, it is still possible that prayers for the dead might have another effect. For example, some people in the Bible were raised from the dead. I would not say that we should expect this to be normative in our day. Nevertheless, a prayer that someone be returned from the dead is not without biblical warrant.
Answer by Ra McLaughlin
Ra McLaughlin is Vice President of Finance and Administration at Third Millennium Ministries.