The Witch King versus . . . Elrond?

Originally Posted by Knight of Gondor

Question: Is Tom Bombadil greater than Gandalf?

Depending on how much power one reads into the concept of how great a threat one can pose to one's enemies, this indicates that Gandalf is greater in might, even than Iarwain.

Bombadil may be Eru himself in the human form, with Gandalf being his greatest servant. If not, then what is Bombadil, & how could you comprehend his power, given that it would take the entire force of Mordor & Sauron to bring him down?