Which day and hour is, "that day and hour", that Jesus mentioned?

Mathew 24:35 Heaven and earth shall pass away, but my words shall not pass away.
  36 But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only.
  37 But as the days of Noe were, so shall also the coming of the Son of man be.

Is he referring to the day and hour of the coming of the Son of man, that he mentioned in the following line?
Or is he referring to the day and hour that the heaven and earth shall pass away, that he mentioned in the previous line?

The coming of the Son of man is detailed in Revelation 19:11-21.
Also, the heaven and earth passing away, is detailed in Revelation 20:11

Or could he be referring to the day and the hour of both events, when he said that no man or angel knows?
Also, isn't it true that no man or angel also knows which day and hour that the blessed hope will be?

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