Many interpreters generally regard 1 Cor 15:29 as one of the most difficult verses in the New Testament. It was certainly not difficult for the Corinthians, but two millennia later, it is difficult for modern Christians. In fact it was a source of discussion even for the Greek Fathers. There are over 40 different interpretations of the verse. Each one usually finds a way to redefine one of three words: Baptism, For, or the Dead. However, one of the pitfalls when approaching such a verse is to miss to forest for the trees. The details of the verse are quite difficult since it seems to teach baptism on behalf of those who have died, but the meaning of the verse in the argument should not be missed.
Paul is clearly saying that there is something about the baptism that the Corinthians were practicing that demands a recognition of a future physical resurrection of all believers. This is a wonderful truth we should never overlook. As a pastor, when I visit someone who has lost a loved one, I have the opportunity to encourage them with this truth of a future resurrection. As a Christian, this truth is a motivation for my Christian walk. This life is fleeting, but there is a time in eternity that I will be free from sin and death. What a wonderfully motivating truth.