Parallel
Hebrews 12:27
Patriarchal Greek New Testament (1904) · Berean Standard Bible
τὸ δὲ ἔτι ἅπαξ δηλοῖ τῶν σαλευομένων τὴν μετάθεσιν ὡς πεποιημένων, ἵνα μείνῃ τὰ μὴ σαλευόμενα.
The words “Once more” signify the removal of what can be shaken—that is, created things—so that the unshakable may remain.