What does Paul say about Christians if there is no resurrection?
Paul says that if there is no resurrection from the dead, then Christ is not risen, and if Christ is not risen, preaching and faith are vain. Christians who faithfully attend church and engage in Christian activity would be, of all people, most foolish, wasting their time.
Les explains that Paul was likely addressing Sadducees in Corinth, since they rejected resurrection from the dead as foolishness. Paul argues that if there is no resurrection from the dead, then Christ is not risen. And if Christ is not risen, then preaching is vain and faith is also vain. Everyone who ascribes to some form of Christianity, who is faithful in churchgoing and Christian activity, would be most foolish if there is no resurrection. They would be wasting their time, because it would make no sense to sit in the pew and sing hymns of the faith if there is no resurrection from the dead. Paul uses this as his argument.