A day is coming when believers will be “caught up” (1 Thess. 4:17) and will meet the Lord in the air. That is the blessed hope for believers today (Titus 2:13)! That generation of Christians will move from earthly mortality to heavenly immortality. What a joyous day for those in Christ! But it begs the question: what is in store for those who are not in Christ? What does the future hold for those who are alive but are not “caught up,” and why do we need to be concerned about it? (Matt. 24:15–21; Revelation)