The “Son of Man” is presented in Daniel 7:13 when Daniel observes in a vision a person he identifies as “a son of man” who appears before God (“the Ancient of Days”). Daniel says that this “son of man” who had entered the presence of God with “the clouds of heaven”:
“was given dominion and glory and a kingdom, that all peoples , nations, and languages should serve him; his dominion is an everlasting dominion…”
The fulfillment of Daniel’s vision that shows this “son of man” receiving the divine authority from God to rule an everlasting kingdom is the glorification that Jesus is referring to when he says:
“The hour has come for the Son of Man to be glorified.” (John 12:23)
Jesus knows the time has come for his enthronement over the Kingdom of God. This is his glorification. But, first the Son of Man must suffer just like “a kernel of wheat falls to the ground and dies” so that “it produces many seeds.” (John 12:24)
The Jews understood from the Old Testament that the anointed Son of Man would appear from the lineage of David to rule an eternal kingdom. But, Jesus was the first to clearly connect the verses about the glorification of the Son of Man with verses from Isaiah concerning the suffering servant. Isaiah had written:
“He was despised and rejected by mankind,
a man of suffering, and familiar with pain.
Like one from whom people hide their faces
he was despised, and we held him in low esteem.
Surely he took up our pain
and bore our suffering,
yet we considered him punished by God,
stricken by him, and afflicted.
But he was pierced for our transgressions,
he was crushed for our iniquities;
the punishment that brought us peace was on him,
and by his wounds we are healed.” – Isaiah 53:3-5
Jesus taught his disciples that the messianic Son of Man would have to suffer as the Servant of God on his way to glorification and his eternal dominion. For example:
“He then began to teach them that the Son of Man must suffer many things and be rejected by the elders, the chief priests and the teachers of the law.” - Mark 8:31
“As they were coming down the mountain, he charged them to tell no one what they had seen, until the Son of Man had risen from the dead.” – Mark 9:9
Isaiah wrote that because God was pleased with the work of the Suffering Servant this servant would be highly exalted. The Suffering Servant would be glorified as the Son of Man:
“Behold, my servant shall act wisely; he shall be high and lifted up, and shall be exalted…kings shall shut their mouths because of him.” – Isaiah 52:13-15