Why Did Jesus Say, "Stay Awake!"?

Why did Jesus warn his followers to "stay awake" and "be prepared" (Matthew 24:37-44)? Why would he bring up Noah and the story of the Flood? Americans are very future-planning, but not ancient believers -- why? How can we distinguish what Jesus said early in the first century from what his later followers claimed he said decades later? #jesus #biblestudy #advent #christmas