Which mountain are Believers at?

Heb 12:17 For you know that afterward, when he (ESAU) desired to inherit the blessing, he was rejected; for he did not find any place of repentance, though he sought it carefully with tears).

Heb 12:18 For you have not come to the mountain that might be touched and that burned with fire, nor to blackness and darkness and tempest,
Heb 12:19 and the sound of a trumpet, and the voice of words (which voice they who heard begged that a word should not be spoken to them any more,
Heb 12:20 for they could not endure the thing commanded, "And if so much as a beast should touch the mountain, it shall be stoned or thrust through with a dart,"
Heb 12:21 and so fearful was the sight that Moses said, I exceedingly fear and quake).

We have not come to Mount Sinai.. where Moses gave the Law. The Law of which was later instructed by God to be placed in the Ark, under the Mercy seat. God prefers mercy over judgement.

Heb 12:22 But you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to an innumerable company of angels,
Heb 12:23 to the general assembly and church of the first-born who are written in Heaven, and to God the judge of all, and to the spirits of just men made perfect,
Heb 12:24 and to Jesus the Mediator of the new covenant, and to blood of sprinkling that speaks better things than that of Abel.

Here God is called the Judge. It comforts us that He has judged us righteous in Jesus' blood. We have been made just/righteous men, and made perfect. His blood speaks better things than Abel's. Genesis 4:10

Heb 12:25 See that you do not refuse Him who speaks. For if they did not escape, those who refused him that spoke on earth, much more we shall not escape if we turn away from Him who speaks from Heaven,

Here, what He speaks, is the better things!

Heb 12:26 whose voice then shook the earth; but now He has promised, saying, "Yet once more I will not only shake the earth, but also the heavens."
Heb 12:27 And this word, "Yet once more," signifies the removing of those things that are shaken, as of things that have been made, so that the things which cannot be shaken may remain.

Here, when we listen to God, when we flow with Him, He shakes our lives. Shakes us of the things that can be removed, leaving the eternal things. Reminds me of wood, hay, straw, gold, silver, precious stones.

Heb 12:28 Therefore, since we are receiving a kingdom that cannot be shaken, let us have grace, by which we may serve God acceptably with reverence and godly fear,
Heb 12:29 for also, "Our God is a consuming fire."

So let us have grace. It is by grace, that we serve God. Our fear of God should not be one of slavery fear. But of godly fear. It is by grace.