Which mountain really is the one which will become firmly established above the top of the mountains? Comparing the first verses of Isaiah chapters 1,2 & 3:
1 The Vision of Isaiah, the son of Amoz, that he visioned, concerning Judah and Jerusalem, in the days of Uzziah, Jotham, Ahaz and Hezekiah, kings of Judah (Isaiah 1).
1 The thing that Isaiah, the son of Amoz, visioned concerning Judah and Jerusalem: And it must occur in the final part of the days, the mountain of the house of Jehovah will become firmly established above the top of the mountains, and it will certainly be lifted up above the hills, and to it all the nations will stream (Isaiah 2).
1 For look! the true Lord, Jehovah of armies, is removing from Jerusalem and from Judah, support and stay, the whole support of bread and the whole support of water (Isaiah 3).
We see that all three chapters are part of the same vision and therefore have the same fulfillments. We know that chapter two has a fulfillment in what we call the last days. We know that this fulfillment relates to us. Therefore all three chapters have a fulfillment that relates to us, and in particular chapter 1 has a fulfillment that relates to us. It is therefore a judgement on spiritual Israel, the new covenant saints, in the present fulfillment. Furthermore, the nations do not stream to the house of David on mount Zion, the mountain of FDS3, they stream to the house of Jehovah on mount Moriah, the mountain of FDS4.
Mount Zion, in Jerusalem, where King David's Palace was, where the sons of the Davidic covenant reigned, symbolises the heavenly rulership over the earth and over the Kingdom of God, for this is where King Jesus, David's son, and father, has his palace in heaven.
Mount Moriah, on the other hand, where Solomon's temple stood, where the priests of the Levitical covenant worshipped, symbolises a second administration, which must be on earth.
So here is your judgement from Isaiah you brothers of Jesus, and you sons of his through the New covenant:
4 Woe to the sinful nation, the people heavy with error, an evildoing seed, ruinous sons! They have left Jehovah, they have treated the holy one of Israel with disrespect, they have turned backwards (Isaiah 1).
The primary part of the seed was the Christ, the secondary part is spiritual Israel, so since he was not particularly evildoing this scripture refers to spiritual Israel.
15 When you spread out your palms, I hide my eyes from you (Isaiah 1).
21 Oh, how the faithful town has become a prostitute! (Isaiah 1).
30 For you will become like the foliage of a big tree which is withering, and like a garden that has no water (Isaiah 1).
No bread and no water, symbolise no spiritual food and no baptising ability. The big tree is that of Daniel 4, the Gentile times - see . The reader can make his/her own interpretation of how Isaiah chapter1 relates to spiritual Israel, the new covenant saints, based on the knowledge that if chapter 2 applies today, then since it's all one vision, chapter1 must also apply today.
At the end of the day, Jerusalem had two mountains. There is no denying this. In fact the whole city was cut in two on this basis, just like the faithful slave - see . For the slave and Jerusalem are the current and ancient administrations of God's people. Two mountains mean two rulerships. So each time Jesus is present, he rules through his capital city, which has two mountains, two Faithful and Discreet Slaves. Therefore there are two such slaves in each presence, a mountain for a slave I am giving you...
34 By the number of the days that you spied out the land, 40 days, a day for a year, a day for a year, you will answer for your errors 40 years, as you must know what my being estranged means (Numbers 14).