God has appointed His people as watchmen to warn the world of spiritual dangers in these last days. The Three Angels' Messages of Revelation 14 contain the entire gospel and unmask Satan's deceptions. Literature distribution plays a crucial role in spreading this final warning, with books like 'The Great Controversy' having special importance. Even when books aren't immediately read, God ensures they'll be found when needed. Through simple methods and ordinary people, God will finish His work, with thousands being converted in a single day, many through reading Adventist publications.