And the walls came tumbling down...

In Acts 10, we see the walls of prejudice come down regarding the Gentiles. Peter was a Jewish man who didn't associate with Gentiles because he did not want to be unclean according Jewish law. God told him to eat "common things" that where against tradition and Peter said "Not so, Lord!" How was the Great Commission to be accomplished if they stayed in Jerusalem? Why was Peter used and not Philip who lived in Caesarea?