Yet once, it is a little while; ἔτι ἅπαξ; Adhuc unum modicum est (Vulgate), The writer of the Epistle to the Hebrews (12:26, 27) quotes and founds an argument on this rendering of the LXX. The expression is equivalent to "once again within a little time."
I will shake, etc. Some difference of opinion exists as to the events here adumbrated. All, however, agree in seeing an allusion to the promulgation of the Law on Mount Sinai, which was accompanied with certain great physical commotions (see Exodus 19:16; Psalms 68:7, Psalms 68:8), when, too, the Egyptians were "shaken" by the plagues sent on them, and the neighbouring nations, Philistia, Edom, Moab, were struck with terror (Exodus 15:14:16).
This was a great moral disturbance in the heathen world; the next and final "shaking" will be under the Messianic dispensation for which the destruction of heathen kingdoms prepares the way. The Israelites would soon see the beginnings of this visitation, e.
g. in the fall of Babylon, and might thence conclude that all would be accomplished in due time. The prophet calls this interval "a little while" (which it is in God's eyes and in view of the vast future), in order to console the people and teach them patience and confidence.
The final consummation and the steps that lead to it in the prophet's vision are blended together, just as our Lord combines his prediction about the destruction of Jerusalem with details which concern the end of the world.
The physical convulsions in heaven and earth, etc; spoken of, are symbolical representations of political revolutions, as explained in the next verse, "I will shake all nations," and again in Haggai 2:21, Haggai 2:22.
Other prophets announce that Messiah's reign shall be ushered in by the overthrow or conversion of heathen nations; e.g.. Isaiah 2:11, etc.; Isaiah 19:21, Isaiah 19:22; Daniel 2:44; Micah 5:9, etc.