“For as the lightning, when it lightens out of the one part under the heaven, shines to the other part under heaven, so shall the Son of man be in his day.”
For when He comes He will be revealed in splendour and glory (compare Luke 8:29) in the same way as the lightning lights up the whole heavens. There will be no mistaking it. Every eye will see Him, and those also who pierced Him (Revelation 1:7). The splendour and glory of His appearing will be manifested to all (Luke 9:26; Luke 21:27).
Thus any future activity of the Son of Man once He has been take out of the world by suffering, will be cosmic. He will rise as the Lord of glory, He will be in Heaven as the Lord of glory, and He will return as the Lord of glory. By this He is building on all the claims that He has made up to this point and adding to them. He is revealing His unique God-likeness.