The shaking of the heaven and earth.

Hebrews 12:26-29 "Yet once more I shake not only the earth, but also heaven." Now this, "Yet once more," indicates the removal of those things that are being shaken, as of things that are made, that the things which cannot be shaken may remain. Therefore, since we are receiving a kingdom which cannot be shaken, let us have grace, by which we may serve God acceptably with reverence and godly fear. For our God is a consuming fire.

In Hebrews, the author which I believe is Paul is referring to the establishment of the first covenant and the new covenant. He begins by saying that the Lord would not only shake the earth, but also heaven earth during the establishment of the New Covenant (12:26a) "Yet once more I shake not only the earth, but also heaven." Now this, "Yet once more," indicates the removal of those things that are being shaken, as of things that are made, that the things which cannot be shaken may remain.
What are the things that are made that can be shaken? The Temple, and priest hood and all the copies and shadows that were made under the literal Jewish kingdom. What were the thing that remained which cannot be shaken? Paul gives us the answer in verse 28. Therefore, since we are receiving A KINGDOM WHICH CANNOT BE SHAKEN, let us have grace, by which we may serve God acceptably with reverence and godly fear.

This passage is as close to any eschatology passage that one will find in the Letter to the Hebrews, with reference to the eschatological kingdom. As such, it clearly refers to a removal of the temporal reality.

The New Testament writers often borrowed highly figurative apocalyptic language that used by the prophets of the Old Testament. In these verse Paul is borrowing the language from the prophet Haggai as he refers to shaking of the heavens and the earth, when God spoke to Israel after coming out of Egypt. Haggai 2:5-7 'According to the word that I covenanted with you when you came out of Egypt, so My Spirit remains among you; do not fear!' "For thus says the LORD of hosts: 'Once more (it is a little while) I will shake heaven and earth, the sea and dry land; 'and I will shake all nations, and they shall come to the Desire of All Nations, and I will fill this temple with glory,' says the LORD of hosts.

In the same way that the Lord shook the heaven and earth, (not literally ) in Haggai 2:5-7 so God will shake the heavens and the earth as part of the new covenant. This second shaking will result in the removal of all created things, so that only that which is uncreated, that which cannot be shaken, will remain.

In Hebrews 12:28b, the author or Paul exhorts his readers to give thanks or to show gratitude for the promise of receiving a kingdom which cannot be shaken, To do so is to worship God with reverence and awe, which is pleasing to God.

He adds that God is a consuming fire, which seems to be a reason for regarding God with reverence and awe. The reference to God in Hebrews 12:29 as a consuming fire is an allusion to Deuteronomy 4:24, where Moses warns the Israelites against idolatry: "For Yahweh, your God, is a consuming fire, a jealous God" (see also Deuteronomy 9:3; Exodus 24:17). God destroys all that which is temporal and disobedient.

The use of the metaphor of consumption by fire to depict God's judgment occurs elsewhere in the Old Testament Isaiah 33:14 The sinners in Zion are afraid; Fearfulness has seized the hypocrites: "Who among us shall dwell with the devouring fire? Who among us shall dwell with everlasting burnings?"