"Jonah was a 'sign' to the Ninevites in that he appeared as one delivered from death. It was the knowledge of this which attested his preaching and caused their repentance. The point of the comparison with Jonah lies, therefore, in 'the authorization of the divine messenger by deliverance from death'. Jesus' preaching, which his hearers are rejecting, will in due course be attested by a still greater deliverance; therefore their condemnation will be the greater (verse 41).
We would like to share some worth-while quotes from various authors to make you pause and consider different aspects of what God's Word teaches.