The Jews expected the Christ or Messiah to be a powerful king because the Old Testament says so many times. But it also says many times that the Messiah would suffer, and that was what Paul was telling the Jews. (See: [[rc://en/tw/dict/bible/kt/christ]])
Paul said that the Athenians were "religious," but they did not worship the true God. They worshiped many different false gods. In the past they had conquered other peoples and begun to worship the gods of the people they had conquered. (See: [[rc://en/tw/dict/bible/kt/falsegod]])