Both ancients and moderns sometimes prefer mountain settings to the formal worship which God has commanded, both Old Testament and New Testament. When King Balak was trying to get Balaam to help him, it says,

“It happened in the morning, that Balak took Balaam, and brought him up into the high places of Baal; and he saw from there the utmost part of the people.”
Num 22:41 WEB

So “the high places” became a snare to Israel

It says even of Solomon, even at the time when God was truly blessing to him,

“Solomon loved Yahweh, walking in the statutes of David his father: only he sacrificed and burnt incense in the high places. ”
1Kgs 3:3 WEB

It was overlooked by God at that time, but later it became a snare to Solomon, and to Israel.

“For they also built them high places, and pillars, and Asherim, on every high hill, and under every green tree;”
1Kgs 14:23 WEB

Then the high places became places to practice all that was wicked and evil in religion.

“The children of Israel did secretly things that were not right against Yahweh their God: and they built them high places in all their cities, from the tower of the watchmen to the fortified city; ”
2Kgs 17:9 WEB

And some mountains oppose others

“15 The mountains of Bashan are majestic mountains.
The mountains of Bashan are rugged.
16 Why do you look in envy, you rugged mountains,
At the mountain where God chooses to reign?
Yes, Yahweh will dwell there forever.”
Psa 68:15-16 WEB

The text goes on of the chariots of God leading from Mount Sinai to God’s Holy Mountain.

“17 The chariots of God are tens of thousands and thousands of thousands.
The Lord is among them, from Sinai, into the sanctuary.
18 You have ascended on high.
You have led away captives.
You have received gifts among men,
Yes, among the rebellious also, that Yah God might dwell there.”
Psa 68:17-18 WEB

Of course Psa 68:18 is quoted in Eph 4:8-10 of Jesus return to heaven to await the last day.

Mystery Babylon is seated on seven mountains

“Here is the mind that has wisdom. The seven heads are seven mountains, on which the woman sits.”
Rev 17:9 WEB

The Greek is indeed mountains, oros in Greek, not hills as it is in some translations. Now ancient Roman was situated on seven hills. Hills, not mountains. Mystery Babylon the Great is seated on seven mountains.

And mountains are allegories of religions

“24 These things contain an allegory, for these are two covenants. One is from Mount Sinai, bearing children to bondage, which is Hagar. 25 For this Hagar is Mount Sinai in Arabia, and answers to the Jerusalem that exists now, for she is in bondage with her children. 26 But the Jerusalem that is above is free, which is the mother of us all.”
Gal 4:24-26 WEB

WEB is the World English Bible, a copyright free revision
of the original ASV American Standard Version 1901