Both of these passages from Isaiah and Ezekiel take place during the Exile of the Jewish people from their land. Because the people were disobedient to the Law, God gave them over to the Babylonians in 586 BC. Here Paul is making a connection with this earlier event: When the Jews lost their land because of disobedience to God, this caused the Pagan nations to blaspheme God. How could God be with the Jews if they were being punished in this way? In the same way, how could God be with the Jews (in Paul’s day) if they were disobeying him (again) in such severe ways?