What you're saying is confusing, because we are given the very image of Christ standing on that mountain immediately beside the ancient city of Jerusalem:
Revelation 14:1-4
1 And I looked, and, lo, a Lamb stood on the mount Sion, and with him an hundred forty [and] four thousand, having his Father's name written in their foreheads.
2 And I heard a voice from heaven, as the voice of many waters, and as the voice of a great thunder: and I heard the voice of harpers harping with their harps:
3 And they sung as it were a new song before the throne, and before the four beasts, and the elders: and no man could learn that song but the hundred [and] forty [and] four thousand, which were redeemed from the earth.
4 These are they which were not defiled with women; for they are virgins. These are they which follow the Lamb whithersoever he goeth. These were redeemed from among men, [being] the firstfruits unto God and to the Lamb.
Those out there whom I've run across at other times, and who habitually spiritualize scripture into making it say what they want, they claim the Lamb is standing on the Zion in Heaven. The problem with that transplanting the imagery into Heaven is that John saw the Lamb on that mountain on earth because he then shifts focus into Heaven, from where the voice comes. The language gives ample indication that the placement of the two are not one and the same. There's Mt Zion, and then there's the voice from another place.
The 144,000 will minister on this earth, not in Heaven. What would be the purpose of that, I have often asked?
We also have Zecheriah 14:4, with Christ standing on the Mount of Olives, which is right there next to the ancient city of Jerusalem. That's not speaking of the time of His earthly ministry.
MM