1 Corinthians 15:13-14

1 Corinthians 15:13-14. But if there be no resurrection of the dead, then is Christ not risen: and if Christ be not risen, then is our preaching vain, and your faith is also vain.

If Jesus Christ did not rise from the dead, we are preaching a falsehood. If he did not rise from the dead, you are believing a falsehood, and our preaching and your believing are nothing but vanity.