I had a holiday in Israel and spent some time in Haifa. The mountain Isaiah refers to is Mt Carmel. Below the mountain is a street known as the walk of the kings and leads straight on to the lower slops of Mt Carmel. The Mormons tried everything the could to buy up land there to fulfil bible prophecy but had no success.
What is there however is the Baha'i Faiths headquarters. The Universal House of Justice and the most amazing terraces and gardens. It's considered the 8th wonder of the world by the people of Haifa.
Now I don't know much about this religion or these Baha'is, but when people go marching up to the house of the Lord, they will be knocking on the door of the Baha'is. Unless some religion can throw them off the mountain they seem to be the ones referenced by that quote.
