The Son of Man
The Son of Man coming in clouds is from Daniel 7:13. This is from a prophetic dream of Daniel about a kingdom that would "devour" the whole world and how it would be replaced by the Son of Man's "everlasting kingdom". "The elect" will be "gathered" from every part of the world and "unto Heaven", a reversal of Zechariah 2:10 where God would come and live among his chosen. God rounding up his chosen people is found in many Old Testament books, but none have the Son of Man doing this, showing how Jesus had altered the prophecies about the messiah