But how will you KNOW when he returns that he the Messiah? Prophecy not considered?
I think it will be very clear.
Firstly, it will be at a time where the majority of believers will be in great need of help, as they will be "on the back foot", as corruption will be uppermost .. even more than it is already.
Secondly, we already have a great deal of knowledge about Jesus' first coming, and Jesus will be coming as the Messiah. and not with any new revelations.
Thirdly, he will appear on this earth near the region of his birth, and will not be registered as being born in any nation.
I'm sure I could come up with more, but that will do for now.