4I have brought you glory on earth by finishing the work you gave me to do.
This is not Jesus’s glory, but the Father’s given by Jesus “by finishing the work you gave me to do.”
5And now, Father, glorify me in your presence…
Now Jesus is asking the Father to glorify “me”, Jesus, “in your presence”, that is to say personally by, and in proximity to the Father.
The next question is, with what should the Father glorify Jesus? Answer:
“…with the glory I had with you before the world began.”
First, the reference point is “before the world began”, ie, pre creation or eternity past. This is the same reference point that John uses in Jn 1:1, “In the beginning”, that is that moment just before “Let there be light” was proclaimed into the darkness!
This Jesus, the Word, was existent in eternity before creation, and the only thing that can exist in eternity is God! This leads to the next point, the only glory in eternity is the glory of God, and the glory of each member of the Godhead is equal in every way.
This is why Jesus said, “…with the glory I had with you before the world began.”
It was a singular and shared glory they all had in their natural state of existence. And now he is asking to have it returned to him.
Doug