Is the Bible True?, page-456

Thanks. This confirms the peaceful, pacifistic teachings of Christ and his early followers.

However since Luke was written some time after the fall of Jerusalem, it is in the style of prophecy that was written after the author had the benefit of hindsight....which does not make it bad advice, or prove or disprove anything about God's existence
or Jesus as Savior.

The Book of Luke was composed several decades after the fall of Jerusalem, by "Theophilus"; it is uncertain who "Theophilus" was, it is a pen-name; also uncertain are what changes and modifications were made to the original before our versions.

I am not an expert on the early Christians, but if Luke was written after Paul, then the warning about fleeing Jerusalem was
a prophecy written by a Christian about something that had already occurred to the Jews at the hands of the Romans decades prior.