Whose voice then shook the earth: but now he hath promised, saying, Yet once more I shake not the earth only, but also heaven. Whose voice then shook the earth - Namely, at the giving of the law on Mount Sinai; and from this it seems that it was the voice of Jesus that then shook the earth, and that it was he who came down on the mount. But others refer this simply to God the Father giving the law.
Not the earth only, but also heaven - Probably referring to the approaching destruction of Jerusalem, and the total abolition of the political and ecclesiastical constitution of the Jews; the one being signified by the earth, the other by heaven; for the Jewish state and worship are frequently thus termed in the prophetic writings. And this seems to be the apostle's meaning, as he evidently refers to Haggai 2:6, where this event is predicted. It may also remotely refer to the final dissolution of all things.