The Christian message has advanced across the world and its impact can be seen everywhere we look. But what is this message and how has it come to bring such change? In the first major speech in the history of the Christian church, we find not only the power that drives this message forward but also the substance of the message itself. Every Christian, from youngest to oldest and from weakest to strongest, has become a preacher and summons all who hear to ‘call out to God to be saved’.