He said to him, "Most assuredly, I tell you, hereafter you will see heaven opened, and the angels of God ascending and descending on the Son of Man."
The title "Son of man" was used at least forty times by Jesus, twelve times in this Gospel; and, with the exception of Stephen's use of it (Acts 7:56), it is found only in our Lord's reference to himself.  There are two questions of the deepest significance that arise from Jesus' use of this title: (1) did he use it in such a manner as to diminish his claim of absolute divinity? and (2) why did he favor this title as distinguished from "Son of God," which was more popularly associated generally with the coming Messiah?