Because he is the Son of man (oti uio anqrwpou estin). Rather, "because he is a son of man" (note absence of articles and so not as the Messiah), because the judge of men must partake of human nature himself (Westcott). Bernard insists that John is here giving his own reflections rather than the words of Jesus and uses uio anqrwpou in the same sense as o uio tou anqrwpou (always in the Gospels used by Jesus of himself). But that in my opinion is a wrong view since we have here ostensibly certainly the words of Jesus himself. So in Revelation 1:13 ; Revelation 14:14uion anqrwpou means "a son of man."