Paul and his friends were accused in Thessalonica of turning the world upside down.
There was an element of truth to the charge. The Gentile world of gross idolatry would soon be overturned by the preaching of Christ; the Jewish church would have to learn that faith in Christ, and not obedience to the moral law, would bring salvation.
The apostles were in fact turning the world the right way up. For they understood not only that Jesus is king but that every earthly king is a shadow and type of the Lord Jesus Christ, the shepherd king.
The proclamation that Jesus and not Caesar is Lord would bring on the early Christians much persecution. And wherever the gospel is proclaimed today it is a call to bow the knee to the King of Kings.