Jesus said, ' therefore keep watch because you do not know on what day your Lord will come.' It is called the day of the Lord set to happen in the future when God will make a new heaven and a new earth. The day only God knows. In this book the author discusses what we can do and prepare ourselves so that we can be included in the new heaven and earth. (The reference scriptures are-Matthew 24:42, 2nd Peter 3:10 and Revelation 21:1)