What does Matthew 24:37 mean?

Christ made it extremely clear that anyone claiming a secret second coming of the messiah is a false teacher (Matthew 24:23–27). Likewise, anyone who attempts to set a date for Christ's return, no matter how vaguely, is ignoring His words. No man can, or will, know exactly when Jesus will return (Revelation 19:11–15) until those very signs begin to happen (Matthew 24:29–31), at which point everyone on earth will know.

The sudden onset of the events which herald Christ's coming will be dramatic. Clear though the signs may be, they will still be surprising to most people in the world. Jesus compares the situation to the days of Noah. His point is not that life on earth will be equally wicked to the days of Noah, necessarily. Perhaps it will, but the main idea is that everything will be in the full swing of "normal life" without anyone suspecting that the time of God's judgment is about to fall (Matthew 24:38).

Even Jesus, Himself, willingly submitting His omniscience to the will of God the Father, does not know when that date will be (Matthew 24:36). Only the Father knows when that specific moment in history will take place. It strains belief to see how people throughout history have attempted to predict the date of Christ's return. Many aspects of Jesus' discourse on the end times are subject to interpretation. That command, however, is as straightforward as can be: "concerning that day and hour no one knows."