I remember as a youngster in Sunday school, perhaps this was true of you, that my Sunday School teachers taught me that Jesus was the Son of God and the "Son of Man." That is to say, He was God’s Son, and He was also human. But when Jesus speaks about Himself as the "Son of Man," He is not simply saying that He has a human nature as well as a divine nature. He is specifically drawing on a picture that He found in the seventh chapter of the book of Daniel, in which you may remember, Daniel has this vision in which he sees the "Son of Man" ascending to the throne of the Ancient of Days as a triumphant victor. And at the throne of the Ancient of Days, He is given the privilege of sharing His triumph with those who are called the "Saints of the Most High."
So in Jesus’ mind, the picture of the "Son of Man" refers not just to his humanity, it refers also to His exultation at the right hand of the Father—His glory and then the expansion of his kingdom that will take place as He is exalted at the Father’s right hand. So when He says “The time has come for the Son of Man to be glorified,” He’s referring to that picture that we were given in the Book of Daniel—the way in which He is going to be exalted at the right hand of the Father. In other words, He is saying His death, His crucifixion is simply the way to His exaltation. We could put it this way, in terms of what we saw at the beginning of John chapter 13, that for Jesus, the way up to the throne of God is the way down to the humiliation of the Cross.