In Luke 22:66-71:
At daybreak the council of the elders of the people, both the chief priests and the teachers of the law, met together, and Jesus was led before them. 67 “If you are the Messiah,” they said, “tell us.”
Jesus answered, “If I tell you, you will not believe me, 68 and if I asked you, you would not answer. 69 But from now on, the Son of Man will be seated at the right hand of the mighty God.”
70 They all asked, “Are you then the Son of God?”
He replied, “You say that I am.”
71 Then they said, “Why do we need any more testimony? We have heard it from his own lips.”
This passage in Luke is more allegorical that Mark's equivalent passage.
In Luke, Jesus talks about the "mighty God" who welcomes in heaven the Son of Man
from that precise moment (as per my interpretation). He has abandoned the earth.
Note the
irony: the sinedrites believe that who is remained before them (after the words "
But from now on, the Son of Man will be seated at the right hand of the mighty God.”) was still the divine Christ...
...but they believe this because the mere man Jesus replied them that :
“You say that I am.”
Hence the circularity of the sinedrite claim of recognition of the Son of God is evident:
The sinedrites believe that Jesus is one who claims that he is the Christ because just
they (!) say that he is the Christ, and they believe to themselves because they believe to the man Jesus.
Hence the sinedrites are condemned to deny the words of the divine Christ:
69 But from now on, the Son of Man will be seated at the right hand of the mighty God.”
...but to accept the words of the mere man Jesus:
“You say that I am.”
For them, the Son of Man is not ascended in heaven just in that moment.
Hence,
they consider as "Son of God" a mere human being who is not the Son of Man (the man Jesus), while in the same time they consider the Son (the divine Christ) as a (mere son of) man (human being).