What will be the celestial sign of Jesus' Second Coming and why will it be important for Christians to recognize it when it appears? These two themes are discussed at length in Jesus' only sermon that fills four chapters of the Bible (Mt. 24-25, Mark 13, Luke 21). In this sermon, Jesus stressed the need for believers to be watchful (for the sign), prayerful, standing firm, fearing nothing and prepared for anything. Prepared believers will have a chance to share their faith during a great revival ending with one-third of all human beings on earth being saved. (Zech 13:9) This book was written as a tool to aid believers in their preparation.