What is the sign of the Son of Man in heaven?
The sign of the Son of Man in heaven is His visible coming in the clouds with power and great glory. After the tribulation's closing days, the tribes of the earth will mourn and see Him with their eyes. This is the Second Coming, when He will stand on the Mount of Olives.
Les explains that this occurs after the events of the closing days of the tribulation. In verse 30, the sign of the Son of Man appears in heaven, and then the tribes of the earth mourn. They will see with their eyes the Son of Man coming in the clouds of heaven with power and great glory. Les suggests that angelic hosts will accompany Him. This is the Second Coming, when He will stand once again on the Mount of Olives. Earlier, Les also mentioned a tremendous increase in highly measured earthquake activity, though he spoke in general terms and did not want to be quoted verbatim.