Why must God become flesh to save men?

For as the lightning, that lighteneth out of the one part under heaven, shineth unto the other part under heaven; so shall also the Son of man be in his day. But first must he suffer many things, and be rejected of this generation. (Luke 17:24–25) (kjv)
From these Bible verses，we can see that the Lord would become flesh when He comes again. Why must God become flesh to save men? This video will tell you the answer.
Recommend a trailer: https://www.holyspiritspeaks.org/videos/awakening-from-the-dream-official-trailer/