1 Corinthians 15:14

and if Christ hath not been raised, then is our preaching vain, your faith also is vain. [The resurrection of Christ was the very heart of the gospel, the essence of gospel preaching. The Corinthians had not realized how serious a matter it was to admit the impossibility of any resurrection. By so doing they made the resurrection of Jesus a fiction, and if his resurrection was fictitious, then Christian preaching and Christian faith were both empty vanities. Verily the argument of the rationalists had proved too much, causing them to deny the very faith which they professed. The apostle goes on to develop this thought, in connection with another thought--the nature of the issue between the rationalists and Christ's ministers. It was not an issue of truth or mistake, but of truth or falsehood--a direct accusation that the apostles and their colleagues were liars-- Acts 2:32; Acts 4:33; Acts 13:30]