A.T. Robertson Commentary Hebrews 12:27

"And this [word], Yet once more, signifieth the removing of those things that are shaken, as of things that have been made, that those things which are not shaken may remain." — Hebrews 12:27 (ASV)

And this word (το δε). He uses the article to point out "ετ απαξ" which he explains (δηλο, signifies, present active indicative of δηλοω).

The removing (την μεταθεσιν). For this word see 7:12; 11:5. For the transitory nature of the world see 1 Corinthians 7:31; 1 John 2:17. "There is a divine purpose in the cosmic catastrophe" (Moffatt).

Made (πεποιημενων). Perfect passive participle of ποιεω. Made by God, but made to pass away.

That those things which are not shaken may remain (ινα μεινη τα μη σαλευομενα). Final clause with μη and the first aorist active subjunctive of μενω. The Kingdom of God is not shaken, fearful as some saints are about it.