“Yea, and we are found false witnesses of God; because we have testified of God that he raised up Christ: whom he raised not up, if so be that the dead rise not. For if the dead rise not, then is not Christ raised: And if Christ be not raised, your faith is vain; ye are yet in your sins” (1 Cor. 15:15–17).
If the dead are not to be raised at the end of history, then Christ could not have been raised in the middle of history. And if there is no resurrection, the Christian faith is vanity. Moreover, Paul continues, if the dead are not raised, then those who testified that God had raised the dead in Christ are guilty of bearing false witness on behalf of God. If the dead are not raised, then God could not have raised the dead. And if the dead are not raised in Christ, then Christian faith is vain, and all Christians are still in their sins. Deliverance from sin is dependent upon deliverance from the dead.
One other important point needs to be made about this passage. Throughout Paul is assuming the absolute authority of logic. For his apostolic argument, he is dependent upon the authority of right reason. If the dead are not raised, then Christ, being dead, could not have been raised. If dead, then not raised. Christ was dead . . . If P, then Q. P, and so therefore Q. This is modus ponens, and therefore valid.
If right reason is not a reflection of the absolute and holy nature of God, then we are still in our sins.