John Wesley on Hebrews 12:26

Whose voice then shook the earth - When he spoke from mount Sinai. But now - With regard to his next speaking. He hath promised - It is a joyful promise to the saints, though dreadful to the wicked. Yet once more I will shake, not only the earth, but also the heaven - These words may refer in a lower sense to the dissolution of the Jewish church and state; but in their full sense they undoubtedly look much farther, even to the end of all things. This universal shaking began at the first coming of Christ. It will be consummated at his second coming. Hag 2:6.