system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] If Glorfindel accompanied the Fellowship, as was considered at the Council of Elrond, would Gandalf have let him help fight the Balrog?

Glorfindel has previously killed a Balrog at Gondolin and we don't know if Gandalf has ever even seen one so Glorfindel might be the most qualified at fighting the Balrog. He might even advise Gandalf to pay attention so not to get dragged down with the Balrog as that is how Glorfindel died the first time.

Would the quote from Gandalf have been "Fly except Glorfindel! This is a foe beyond any of you except Glorfindel. Glorfindel and I must hold the narrow way. Fly except Glorfindel!"?
gpt
Unlikely.  Gandalf knew he had a good shot at killing the Balrog, and the way he tells it once they'd fallen beneath the earth, the Balrog was *running away from Gandalf*.  

But killing the Balrog was never the point, protecting the ring bearer was the point, and the best way to do that was to get as many members of the fellowship away from the Balrog as possible.  However useful Glorfindel may have been in holding off the Balrog, he would be yet more useful remaining with the ring bearer and contributing to the fight against Sauron.