The Athenians listened carefully to Paul until he spoke about the resurrection of the dead (17:31). At that point, some began to laugh and mock him. To Greek listeners, the idea of resurrection seemed foolish (see 1 Corinthians 15:12–19). In a similar way, the Jews in Jerusalem listened to Paul until he spoke about God accepting the Gentiles (Acts 22:22). Then they also rejected his message.
These examples show how the message of the good news can offend people because of their prejudices (strong opinions that keep them from accepting the truth; see 1 Corinthians 1:20–25).